by Ilya Gavrichenkov
09/16/2010 | 05:30 PM
The recent news says that we are not going to see AMD processors with Bulldozer architecture any time soon. They will only arrive half a year from now or even later. Fortunately, it doesn't mean that AMD has no competitive products that might affect the market situation right now. Released in April, the Phenom II X6 series has been a remarkable demonstration of force. Having as many as six full-featured CPU cores, Phenom II X6 processors perform very well in multithreaded applications, being faster than the Core i5 series and even challenging the more expensive models of the Core i7 family.
Intel had not been prepared to such an unexpected success of its archrival. At the moment of the announcement, the Phenom II X6 series proved to be more appealing than other offers available then in the price range of $250-350. Intel had to take some countermeasures.
After a few months we can see the numerous consequences of the arrival of inexpensive six-core CPUs from AMD. First, Intel has offered an overclocker-targeted series of CPUs. AMD's top-end processors can be overclocked by means of increasing their frequency multiplier, so Intel has implemented the same solution in its quad- and dual-core K series processors. Second, the junior Core i7 model has become considerably cheaper. The Core i7-860 now costs about the same money as the Phenom II X6 1090T. And third, senior Core i5 series models have increased their clock rates. A quad-core Core i5-760 and a dual-core Core i5-680 are now available in shops.
Among all these measures that Intel has taken to make its products more appealing we find the release of the new CPU models the most exciting. We mean the Core i5-760 in particular. This model comes at a recommended price of $205 and can be viewed as an improved alternative to the highly popular Core i5-750 which has become one of the most widespread LGA1156 processors thanks to its Lynnfield core and affordable price. That's why we are so interested in taking a closer look at its successor Core i5-760.
The Core i5-760 doesn't differ much from its predecessor Core i5-750. In fact, we can only see a small growth in clock rate. It is higher by 133 MHz, so the new model has a default clock rate of 2.8 GHz. Otherwise, it is the same quad-core Lynnfield which does not belong with the Core i7 family only because it lacks Hyper-Threading technology.
The following table sums up the Core i5-760 specs:
The Core i5-750 having been the junior quad-core LGA1156 processor, Intel did not need a new core stepping to produce the new model with a slightly higher clock rate. The i5-760 is based on a stepping B1 core, just like Lynnfield processors released a year ago. You can easily see it, for example, in this CPU-Z screenshot.
Despite the old stepping, we can see that the CPU voltage is rather low. Indeed, although the top default voltage for the Core i5-760 is 1.4 volts (the same as for the Core i5-750), the new processor actually works at much lower voltages.
Comparing the Core i5-750 with the new model, we can also note that the latter has more aggressive Turbo Boost technology. The Core i5-750 could increase its frequency multiplier by 4 under low loads, reaching a clock rate of 3.2 GHz whereas the Core i5-760 can increase it by 5 and reach a clock rate of 3.46 GHz. The frequency multipliers available for the Core i5-760 with Turbo Boost are listed in the following table:
Thus, the Core i5-760 looks more like a top-end CPU than the Core i7-860 in terms of its frequencies in default and Turbo modes.
Considering the increased default clock rate and the more aggressive Turbo mode, we can even view the Core i5-760 as virtually identical to the higher-class Core i7-860 with Hyper-Threading turned off but we should not forget that, besides the lack of Hyper-Threading, quad-core Core i5 processors differ from their senior cousins in one thing more: they have fewer memory frequency multipliers. As a result, the Core i5-760 can only support DDR3-1067 and DDR3-1333 unless you increase the base clock rate. The Core i7 series additionally supports DDR3-1600.
The Core i5-760 is targeted at the mainstream market and priced accordingly. Intel seems to pit it against the six-core Phenom II X6 1055T, so we will compare these two CPUs in the first place. Besides, we will pinpoint the exact position of the new CPU among Intel's products by including similarly priced processors from the Core i7, Core i5 and Core 2 Quad series into this test session. Here is the full list of components we used:
The Core i5-760 and Core i5-750 processors do not support DDR3-1600. Therefore we tested them with DDR3-1333 at 9-9-9-27 timings. The same is true for the LGA775 platform with the Core 2 Quad Q9500 processor.
SYSmark 2007 shows the performance of a computer when executing typical scenarios in popular office and digital content creation applications.
This benchmark prefers Intel's Core i5 and Core i7 processors because the applications it employs usually cannot run in multiple parallel threads. As a result, the Phenom II X6 proves to be unable to show its best and falls behind the new Core i5-760 as well as the older Core i5-750.
Comparing the Core i7-860 with the Core i5-760, we can see that the senior model enjoys but a 3% advantage thanks to its Hyper-Threading and faster memory.
To show you the complete picture, here is a table with the SYSMark results sorted by application type.
As you know, it is the graphics subsystem that most often determines the overall performance of a computer in modern games if the CPU is fast enough (and the $200 CPUs we are testing today are indeed fast). Therefore we run gaming tests in our CPU reviews without full-screen antialiasing and at low resolutions. So, the results are not indicative of how fast the particular game can run on modern computers but rather how well the tested CPUs can cope with gaming load. This can give us some insight into the future when graphics cards will get faster and the CPU may become the limiting factor.
Games are not the kind of applications to make good use of multithreading. Therefore the Core i5-760 is roughly as fast as the Core i7-860. The latter enjoys a small advantage thanks to working with faster system memory which is important for games. Thus, the Core i5-760 (and its predecessor) is fast enough to be used in a high-performance gaming computer.
The competing offer from AMD, Phenom II X6 1055T, cannot boast such a high speed. It is slower in nearly every of the gaming tests and is less appealing for gamers. The six-core processor from AMD is only competitive to Intel's previous-generation Core 2 Quad series.
WinRAR cannot run in more than four execution threads when archiving data and cannot utilize the extra cores of a six-core CPU or Hyper-Threading technology. As a result, the Core i5-760 is much faster than the Phenom II X6 1055T and is almost as fast as the Core i7-860.
The TrueCrypt encryption tool, on the contrary, can run in multiple parallel threads effectively: the Core i5-760 is 26% behind the Core i7-860 and 54% behind the Phenom II X6 1055T.
Video encoding and nonlinear video editing are popular tasks that call for advanced hardware resources. Here, the more physical or virtual cores a CPU has, the better it performs. Such CPUs are much faster than the ordinary quad-core Core i5-760.
On the other hand, such multi-core CPUs do not enjoy a large advantage in Photoshop or when encoding audio in iTunes.
Final rendering can be done in multiple execution threads very efficiently, so the Core i5-760 doesn't look good against its opponents. The higher clock rate makes it 4% faster than its predecessor but not equal to the higher-class models from Intel or to the similarly priced six-core CPUs from AMD.
There should be no surprises about the power consumption of the Core i5-760. Its clock rate is similar to that of the Core i5-750 and it has an old core stepping. Its specified electric and thermal properties have not changed, either. However, we shouldn't forget that a year has passed since the release of early Lynnfield processors and their 45nm tech process has become far more optimized. As a result, the new CPU can work at a lower voltage even though this is not explicitly marked in its specs.
Our sample of the Core i5-760 is designed for a voltage of 1.125 volts, which should have a positive effect on its power consumption. 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 each of the system components. The PSU's efficiency is not taken into account. The CPUs are loaded by running the 64-bit LinX 0.6.3 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.
We might have expected the Core i5-760 to be more economical than its predecessor under load. We got our test sample of the Core i5-750 processor about a year ago and it works at a higher voltage of 1.225 volts. Quad-core Core i5 series processors are generally more economical in comparison with both the Phenom II X6 and Core i7 series. However, it is the 32nm dual-core Core i5 series and, rather surprisingly, the old Core 2 Quad series that are the most economical among $200 processors.
Improved manufacturing process may also improve a processor's overclockability. So, we tried to accelerate our Core i5-760. Since it does not belong to the overclocker-friendly K series, it could only be overclocked by increasing the base clock rate above the default 133 MHz.
We can remind you that Core i5 series Lynnfield processors can usually work at a clock rate of about 4.0 GHz after a small increase in their voltage.
The Core i5-760 carries this tradition on. We increased its voltage to 1.4 volts (which is perfectly safe as it is within the processor's specified voltage range) and overclocked our sample to 4.2 GHz.
The overclocked CPU passed every stability check, its maximum temperature never being higher than 89°C.
To get a notion of the performance of an overclocked quad-core Core i5, you can refer to our Phenom II X6 1055T review where we compared the two CPUs at default and overclocked frequencies.
Frankly speaking, we had not expected much from the new quad-core model in the Core i5 series before we tested it. Its clock rate is a mere 133 MHz higher than that of its predecessor, which is not much of an improvement. However, the Core i5-760 proved to have a lot of other benefits besides the clock rate. First of all, its Turbo Boost technology is set up in a more aggressive way and increases its clock rate under single-threaded load by 266 MHz above that of the Core i5-750. Second, the Core i5-760 is more economical than the Core i5-750 processors we tested before. And third, the polished-off tech process has improved the overclockability of this Lynnfield-core processor.
Thanks to all these small enhancements, the Core i5-760 looks definitely more appealing than its predecessor. What is especially nice, its price is a mere $9 higher than that of the Core i5-750, so Intel has got a very competitive product in the $200 segment. This product can not only compete with AMD's six-core CPU but can also challenge the more expensive Core i7-860 which only differs from the Core i5-760 in its support of Hyper-Threading (which is not always a useful technology) and faster system memory (DDR3-1600).
To illustrate our point, we can show you a diagram with the average performance and price of the tested CPUs.
Although the Core i5-760 has a good position in the diagram, we wouldn't want to talk much about how perspective this new Lynnfield model may be. Yes, it is interesting now, but its lifecycle may prove to be too short. In January Intel will introduce the Sandy Bridge processor series which will use a completely new platform and push the performance bar much higher in every price category. Therefore, purchasing any LGA1156 processor, including the Core i5-760, may be not advisable today. That's why we don't think the new CPU will have the time to become as popular as the Core i5-750, yet it will surely find its customer, too.