Intel Pentium G850, Pentium G840 and Pentium G620 Review

Intel is now offering dual-core Sandy Bridge processors under Pentium brand. They lower the price for the “LGA1155 Club” membership quite noticeably, because they are selling for less than $100 a piece. Does it mean that the new Pentium processors may become a new perfect combination of performance and price? Let’s find out!

by Ilya Gavrichenkov
06/24/2011 | 01:08 PM

Intel is definitely releasing new platforms into the market at a very high pace these days. After getting one new platform each year, we have finally got to the point when there are four current platforms coexisting successfully at the same time: LGA775, LGA1155, LGA1156 and LGA1366, and the fifth one – LGA2011 – is just around the corner. No one is happy about this situation. The users complain that they are constantly forced to upgrade their mainboards and cooling systems, and the manufacturers suffer trying to ensure adequate support to all this diversity.

 

Of course, in the light of this situation Intel decided to slightly slow down and minimize the number of current platforms to something more reasonable leaving only two platforms in the spotlight: a high-performance one and a universal one. In the new world the enthusiasts will get the upcoming LGA2011 systems, while the existing LGA1155 will become a mainstream platform. Its versatility will be not only the result of a “political” move, but it merely follows from the features of the Sandy Bridge processors in general. Second generation Core processors in LGA1155 form-factor can be easily differentiated according to their features, performance and heat dissipation and therefore distributed over different market segments. Besides, the production cost of 32 nm Sandy Bridge processors allows lowering the retail prices of solutions based on this microarchitecture to very democratic levels.

In other words, it is the LGA1155 platform that has every chance to become a fully-fledged successor to LGA775 from 2007-2008 and to get an entire army of processors starting with pretty expensive Core i7 models and finishing with the cheapest Pentium and budget Celeron CPUs. Now there is only one little thing left: Intel has to expand the LGA1155 processors lineup and add less expensive solutions to the already existing Core i3/i5/i7 CPUs. They have already made the first step in this direction: Pentium CPUs on Sandy Bridge microarchitecture have already hit the market. The second step would be the launch of low-cost LGA1155 Celeron processors, which is scheduled to happen this coming September. In other words, LGA1155 platform will become truly versatile this fall already, thus writing off all LGA775 and LGA1156 products, which so far remain pretty popular due to their relatively affordable prices.

This is what the LGA1155 processor lineup will look like in the nearest future (energy-efficient S- and T- series processors are not taken into account in this table):


*Celeron processors for LGA1155 haven't been announced yet

Today we are going to talk about new Pentium processors that look like quite normal dual-core CPUs and seem to be a pretty appealing option for inexpensive mainstream systems. Although they do not support Hyper-Threading like Core i3 and have a simpler graphics core modification inside, their rather high clock frequencies should let them hold their head up high.

Closer Look at Pentium G850, G840 and G620

Since NetBurst microarchitecture was retired for being unable to meet all the expectations, Pentium branded processors have been positioned as inexpensive solutions with average performance. According to Intel, it is not quite an entry-level solution, but it definitely yields to fully-fledged Core processors quite significantly.

The logic behind Pentium processors design is fairly simple: they take Core i3 CPUs, slightly lower their frequency and disable their most appealing features. As a result, we have a fully operational and pretty fast LGA1155 processor, which, however, doesn’t let you fully enjoy the benefits of Sandy Bridge microarchitecture, for which you will have to consider Core i3 or even pricier models.

In other words, Pentium looks very similar to Core i3 at first glance. At least, both of them have two computational cores, an integrated HD Graphics core inside and have 3 MB of L3 cache memory shared between all cores. However, the list of things missing in Pentium 3 is quite long and includes a lot of things that are considered to be key features of the Sandy bridge microarchitecture:

LGA1155 Pentium processors family includes three models - G850, G840 and G620 that differ only in their clock speeds – and a fourth G620T model that belongs to the special energy-efficient series. The TDP of regular Pentium processors is 65 W, which is typical of dual-core Sandy Bridge CPUs, while the T-model boasts 35 W TDP.

The formal specifications of the 65 W CPU models discussed in our today’s review are summed up below:

Here are a few CPU-Z screenshots for your reference:

Testbed Configuration

Since Intel is currently shipping Pentium processors for three different platforms we had to include a pretty substantial number of LGA775, LGA1155 and LGA1156 processors. Among them are three different types of Pentium CPUs, LGA1155 and LGA1156 Core i3 processors and even a Core 2 Duo. Besides, similarly priced dual- and triple-core Socket AM3 processors will also compete in our today’s test session.

As a result, we put together systems featuring the following hardware and software components:

Performance

General Performance

To estimate the performance in general-purpose applications we used a new benchmark – Futuremark PCMark 7, which measures the systems performance during execution of typical algorithms. In the end this test generates several scores: total score and computational performance score, as well as performance indexes for office tasks, entertainment applications and HD-content creation and processing tasks.

The diagrams above show that new Pentium processors for LGA1155 platforms do not really stand out among other similar products. It means that Intel decided not to disturb the established market by launching their new Sandy Bridge processors in the sub-$100 price range. According to PCMark 7 results, the main advantage of the new CPUs is not their superb price-to-performance ratio, but their full compatibility with contemporary mainboards, which offers possibilities for simple future upgrades by replacing these processors with faster and more feature-rich ones later on.

However, it doesn’t mean that the new Pentium processors are the same as the old members of this family. Even the junior LGA1155 CPU in the lineup, Pentium G620, is a little faster than the top CPU models for LGA1156 and LGA775 platforms. Moreover, Pentium G850 or Pentium G840 can often compete against the previous-generation Core i3 (Clarkdale). However, the contemporary Core i3-2100 is still unattainable for them. It has higher clock speed and supports Hyper-Threading technology, which turns it into a solution of a different class. Speaking of Socket AM3 processors, we can state that the new LGA1155 Pentium CPUs are fully-fledged competitors to dual- and triple-core Athlon and Phenom II processors.

Gaming Performance

As you know, it is the graphics subsystem that determines the performance of the entire platform equipped with pretty high-speed processors in the majority of contemporary games. Therefore, we do our best to make sure that the graphics card is not loaded too heavily during the test session: we select the most CPU-dependent tests and all tests are performed without antialiasing and in far not the highest screen resolutions. In other words, obtained results allow us to analyze not that much the fps rate that can be achieved in systems equipped with contemporary graphics accelerators, but rather how well contemporary processors can cope with gaming workload. Therefore, the results help us determine how the tested CPUs will behave in the nearest future, when new faster graphics card generations will be widely available.

 

What we see in contemporary games is very much different from what we have just seen in PCMark 7. In fact, it isn’t surprising at all, especially if we recall how Sandy Bridge processors performed in gaming tests before. New Intel microarchitecture is very well fit for gaming load that is why the new Pentium processors do really well in this group of tests. This entire family is quite comparable with Core i3 LGA1156 processors, so they fit perfectly for inexpensive gaming systems. Only more expensive Core i3 LGA1155 processors and in some cases Athlon II X3 can offer better performance than Pentium G850/G840/G620, when a game uses multi-threading efficiently enough.

Archiving and Encryption

To test the processors performance during data archiving we resort to WinRAR archiving utility. Using maximum compression rate we archive a folder with multiple files with 1.4 GB total size.

Although the memory controller of the new Pentium processors can’t work with anything faster than DDR3-1333, they do very well in data compression tests. Sandy Bridge microarchitecture with highly efficient internal ring bus helps these processors to win the leadership in their price range: no other solutions with comparable price can even get close to Pentium G850/G840/G620.

The processor performance during encryption is measured with an integrated benchmark from a popular cryptographic utility called TrueCrypt. I have to say that it can not only effectively utilize any number of processor cores, but also supports special AES instructions.

As for the cryptographic tests, things are not so rosy for the newcomers here. Intel disabled AES instructions support in their inexpensive processors that is why the number of cores and their clock frequency start to matter most of all. As a result, Pentium G850/G840/G620 do not shine in this test: they are behind not only Athlon II CPUs, but even Pentium E6800 for LGA775 based on the prehistoric Wolfdale core.

Image Editing

We measured the performance in Adobe Photoshop using our own benchmark made from Retouch Artists Photoshop Speed Test that has been creatively modified. It includes typical editing of four 10-megapixel images from a digital photo camera.

The new Pentium G850/G840/G620 processors show their real strengths in this test. And even though they are still quite far behind Sandy Bridge based Core i3, they outperform all older CPUs for different platforms. For example, dual-core Core i3-530 supporting Hyper-Threading is about 10% slower than Pentium G620, while triple-core Athlon II X3 455 loses more than 20%.

We have also performed some tests in Adobe Photoshop Lightroom 3 program. The test scenario includes post-processing and export into JPEG format of a hundred 12-megapixel images in RAW format.

Things are a little different in Lightroom, but overall we can’t complain about low performance of the new LGA1155 Pentium processors. They do just as good as triple-core AMD CPUs and dual-core LGA1156 processors with Hyper-Threading support.

Audio and Video Transcoding

We use Apple iTunes utility to test audio transcoding speed. It transcodes the contents of a CD disk into AAC format. Note that the typical peculiarity of this utility is its ability to utilize only a pair of processor cores.

Strangely enough, the new Pentium processors suddenly yielded to their counterpart for the LGA775 platform. But if we disregard this one incident, then the overall performance of the new Pentium G850/G840/G620 processors will be quite acceptable. Previous-generation LGA1156 Core i3 and Pentium processors as well as dual- and triple-core Socket AM3 CPUs fall far behind our heroes.

In order to measure how fast our testing participants can transcode a video into H.264 format we used x264 HD benchmark. It works with an original MPEG-2 video recorded in 720p resolution with 4 Mbps bitrate. I have to say that the results of this test are of great practical value, because the x264 codec is also part of numerous popular transcoding utilities, such as HandBrake, MeGUI, VirtualDub, etc.

Video transcoding using x264 codec is one of those few tasks where the number of processor cores matters a lot. That is why the new Pentium CPUs can’t really shake the triple-core AMD processor as well as Core i3 CPUs. Although the latter processors are dual-core ones, they support Hyper-Threading technology. As for competition against true dual-core processors, our heroes are definitely in the lead.

The performance in Adobe Premiere Pro is determined by the time it takes to render a Blu-ray project with a HDV 1080p25 video into H.264 format and apply different special effects to it.

This looks very similar to what we have just seen in the previous benchmark. This is quite logical, because both - x264 and Adobe Media Encoder – create the same processor load.

We decided to add Cyberlink Media Espresso 6.5 to the list of benchmarks we use for video content trancoding. This utility is particularly interesting to us because it allows using the graphics accelerator for video transcoding. We measured the time it took to transcode a small 10-minute H.264 1080p video clip into an iPhone 4 friendly format (H.264, 1280x720, 4 Mbps). In all tests we enabled ATI Stream technology supported by our Radeon HD 6970 graphics card, which accelerated the transcoding process.

Compared with what we saw in other video transcoding applications, we do not notice anything new here. The new Pentium G850/G840/G620 yield only to triple-core CPUs or dual-core processors with Hyper-Threading support.

Final Rendering

We use special Cinebench test to measure the final rendering speed in Maxon Cinema 4D.

Rendering, just like video transcoding, is one of those tasks that can use any number of available cores quite effectively. So the outcome of this test was quite expected. New Pentium processors for LGA1155 platform become the fastest dual-core CPUs, but at the same time they are defeated by the triple-core Athlon II X3 as well as the dual-core Core i3 CPUs with Hyper-Threading support, which doubles the number of computational threads executed simultaneously.

Rendering speed in Autodesk 3ds max 2011 with both, Scanline as well as Mental Ray, was measured using SPECapc test.

This is a different rendering application, but the results are practically the same. Pentium G850/G840/G620 processors can’t be regarded as a good choice for serious computational tasks. If you are looking to build an inexpensive system for rendering needs, it would make more sense to go for an inexpensive triple-core AMD CPU, which are currently selling at very democratic prices.

Power Consumption

Pentium G850, G840 and G620 processors as well as Core i3 for LGA1155 formally belong to solutions with 65 W TDP. However, in reality they have lower frequencies and do not support Hyper-Threading and therefore, should be more energy-efficient. Let’s check it out.

The graphs below show the full power draw of the computer (without the monitor) measured after the power supply. It is the total of the power consumption of all the system components. The PSU's efficiency is not taken into account. The CPUs are loaded by running the 64-bit LinX 0.6.4 utility. We enabled all the power-saving technologies for a correct measurement of the computer's power draw in idle mode: C1E, AMD Cool'n'Quiet and Enhanced Intel SpeedStep.

In idle mode Pentium G850, G840 and G620 processors consume about the same as other CPUs for LGA1155 and LGA1156 systems. However, all processors featuring an integrated graphics core lose to their simpler counterparts used in LGA775 and Socket AM3 platforms.

However, it is not the final verdict yet. Like other processors with Sandy Bridge microarchitecture, Pentium G850, G840 and G620 can lower their power consumption in idle mode. In order to accomplish this you will need an Intel P67 based mainboard. These mainboards can disconnect integrated graphics from the power supply completely, which will allow lowering the power consumption by about 4-5 W.

The new Pentium processors proved to be the most energy-efficient solutions among CPUs that do not belong to the specific energy-efficient product series. In other words, they would be a pretty good choice in terms of performance-per-watt and may be really desirable for compact and quiet systems.

If we continue in this direction, we could probably assume that Pentium G850, G840 or G620 could easily become a great alternative to the 35-watt Core i3-2100T, which has proven to be an excellent choice for HTPCs.

Pentium G850/G840/G620 vs. Core i3-2100T

Pentium processors for LGA1155 systems turned out the most energy-efficient processors with 65 W TDP. This thermal envelope has obviously been declared with a significant reserve: even under maximum load they consume considerably less power. However, Intel doesn’t want to set a lower official TDP for marketing reasons. Processors with 45 W and 35 W TDP are part of a separate business for Intel. Products like that are in demand and therefore sell at higher prices.

But we don’t really care much about the official specifications. Therefore, we decided to compare the new Pentium CPUs against one of the energy-efficient LGA1155 Core i3 processors. This comparison poses special interest to us, because CPUs with lower TDP work at lower clock speeds, which means that 65 W Pentium G850, G840 and G620 may suddenly become direct competitors to the 35 W Core i3-2100T. Energy-efficient Core i3-2100T supports Hyper-Threading technology, but its clock frequency is only 2.5 GHz. As for Pentium G850/G840/G620, their Hyper-Threading support is disabled, but their clock frequencies are 100-400 MHz higher.

If the new Pentium processors show similar heat dissipation levels as Core i3-2100T and perform at least as fast as the latter, we will get a great opportunity to save a few tens of dollars on a CPU when building an energy-efficient system.

In fact, we decided to dedicate a separate short test session to investigation of this assumption. Within this test session we tested Mini-ITX platforms built on LGA1155 Pentium processors and Core i3-2100T, which use integrated graphics. Besides, we also tested an LGA1156 platform with Pentium G6960 (Clarkdale generation).

During this test session we used the following hardware and software components for our testbeds:

Let’s start with the most interesting results: the actual power consumption. As always, the numbers below show the power consumption after the PSU and our testing methodology doesn’t take into account any power losses that occur in it.

In idle mode the system with energy-efficient Core i3-2100T inside is about 2-3 watt more economical than a similar platform with Pentium processors. So, we have no formal complaints about CPUs with 35 W TDP. The T-series processor does in fact consume less than the least energy-hungry representative of the 65 W series. However, the practical advantage of only 3 watts is, in fact, negligible. Therefore, we can conclude that Pentium processors look very good in a compact LGA1155 platform, especially against the background of Pentium G6960.

During full utilization of the processors’ computational cores things barely change. Core i3-2100T has a tiny advantage of 3-5 W over the new Pentium CPUs. So, looks like we could really argue about Intel’s positioning of the new Pentium G850, G840 and G620. These processors have every right to be considered energy-efficient, too. And the total power consumption reading for an LGA1155 system with a new Pentium inside is clear indication of that: 35-40 W is very little for an entire platform.

Nothing changes when the heaviest load falls onto Intel HD Graphics core. Systems with Pentium G850, G840 and G620 prove much more energy-efficient than the integrated LGA1156 platforms. Their power consumption readings get very close to that of a platform with a 35 W Core i3-2100T.

Although Quick Sync technology is disabled in Pentium CPUs, the hardware HD video decoder is still there. Therefore, Pentium G850, G840 and G620 based systems consume very little power during video playback.

Overall, LGA1155 Pentium processors look very appealing in terms of power consumption. They will undoubtedly fit perfectly into HTPC or compact and quiet systems concept. The absolute power consumption readings indicate that systems built with them could do just fine with low-capacity PSUs and small cooling systems. The special 35 W processors like Core i3-2100T won’t offer any serious advantage in power consumption aspect over the new Pentiums, even though they are much more expensive.

Maybe the high price of the Core i3-2100T will be justified by their higher performance? Let’s check it out now.

The results of our performance tests can be divided into two groups. The first includes applications that do not always use all available cores and do not fully utilize them.

Here the top LGA1155 Pentium processor can outpace Core i3-2100T due to its higher clock frequency.

The second group includes application that create heavy computational load and distribute the load evenly over all available cores: computational and virtual.

Hyper-Threading technology is of great help here. Due to this technology the OS sees Core i3-2100T processor as a quad-core CPU that is why it runs faster than all Pentium processors, even though its clock frequency is 16% lower.

We should pay special attention to video transcoding speed measured in Cyberlink Media Espresso 6.5. The thing is that this application can benefit from Quick Sync technology present in Core i3, but absent in Pentium.

This is where Core i3-2100T finally justifies its higher price in full. Quick Sync support allows it to transcode HD video three times faster than Pentium processors, which until now seemed like a great alternative. Therefore, if video transcoding is one of your priority tasks, then Pentium G850, G840 and G620 are automatically off your list of options.

The gaming tests showing the performance of the Intel HD Graphics core integrated into the processors are also very interesting.

Although the graphics core in Pentium processors is called HD Graphics, and Core i3-2100T formally has a more advanced version of it called HD Graphics 2000, in reality top Pentium processors outperform Core i3-2100T. The thing is that the number of graphics execution units in different versions of the HD Graphics core is the same, but the graphics core frequency in Pentium is higher than that in the energy-efficient CPU. Besides, don’t forget that Hyper-Threading isn’t that essential for gaming applications anyway.

So, if we compare Core i3-2100T and the new Pentium processors, the only indisputable argument in favor of the more expensive “officially energy-efficient” processor will be Quick Sync support beneficial for video transcoding tasks. In all other cases our assumptions about the new Pentium being fit for HTPC proved totally correct. Only under very heavy computational load Core i3-2100T proves better, but in many other applications it falls behind Pentium CPUs. And the lower Vcore as well as lower TDP of the Core i3-2100T in reality result only in 2-5 W of energy savings at the most.

Conclusion

The commotion caused by the launch of processors on Sandy Bridge microarchitecture created very high expectations for the new Pentium processors. However, Intel had a different plan: these dual-core processors priced below $100 weren’t supposed to disturb the low-end market situation in any way. That is why the average performance of Pentium G850, G840 and G620 is only a little higher than that of previous-generation Pentium processors manufactured for LGA775 and LGA1156 systems. It was achieved by stripping them of some features typical of other more expensive LGA1155 processors.

The new Pentium processors do not support Hyper-Threading and new vector instructions, work at lower clock speeds and do not have Quick Sync. Nevertheless, Sandy Bridge is such an advanced microarchitecture, that it is simply impossible to cut off its entire advantages even if you really wanted to. Therefore, there are certain cases when the new Pentium processors will be way ahead of their predecessors and competitors.

First of all, Pentium G850, G840 and G620 perform impressively fast in games for a product of their price. They will be a great fit for inexpensive gaming machines, as their advantage over dual-core Socket AM3, LGA1156 and LGA775 CPUs is more than obvious.

Secondly, we can definitely recommend these CPUs for HTPC. Despite the declared TDP of 65 W, in reality they are very energy-efficient. In this aspect they are comparable with 35 W Core i3 CPUs from the specific energy-efficient T-series. The same is true about performance. The new Pentium processors on average work just as fast as Core i3-2100T. Their only weakness is video transcoding tasks, where Core i3 may be significantly faster due to Quick Sync support.

Summing everything up we have to welcome the new Pentium processors into this world. They make contemporary Intel platform extremely attractive and expand its application field. It’s been a while since Intel offered a good versatile platform, and LGA1155 has finally got a chance to become one.