Corsair TwinX1024-4000PRO DDR500 Memory Review

We tested one of the latest overclocker’s memory sets from Corsair, which belongs to the ProSeries. And even though they proved to be no ideal solutions, they are really worth your attention. At least we have never seen anything like that: large impressive heat-spreaders with blinking LEDs all over. Wow!

by Ilya Gavrichenkov
10/05/2003 | 01:54 AM

The introduction of new standards in the memory market slowed down a little bit. The last PC3200 SDRAM standard was approved by JEDEC quite a long time ago already and the memory of this time has already become pretty widely spread. We will have to live with PC3200 SDRAM for a considerable while, at least until the middle of next year, when DDR-II SDRAM will start appearing in the market. It is exactly during these slow-down periods that the manufacturers of overclocking friendly memory become more active and start offering faster memory modules than the standard ones.


The today’s fastest “official” memory is DDR400 SDRAM, however, the overclocking memory makers have already learned to produce DDR500 SDRAM and even DDR533 SDRAM. There are not too many companies offering memory solutions like that, however it doesn’t prevent them from being involved into a really cut0throat competition.

The four major makers of overclocker’s memory, namely Corsair, OCZ, Kingston and GeIL, are constantly competing with one another for the right to be the first with the new faster memory modules announcement. However, this competition is also coming to an end. DDR-I standard and the production technologies used by these memory manufacturers seem to have almost exhausted their potential, so that the production of new chips working at even higher frequencies is more frequently connected with tangible expenses and technological difficulties. That is why I can state that the competition between the overclocker’s memory makers has come to a new stage: having reached almost the same frequency they start loading the products with their brand new technologies.

You can clearly see the same situation happening in the mainboard market right now. While most mainboards available in the today’s market boast nearly identical formal specifications, the manufacturers load them with the whole bunch of various “tidbits” and base their ongoing product marketing and promotion on these unique brand name features. Now the makers of overclocking friendly memory are also resorting to the same tricks. The first step here belongs to Corsair Company, which has recently announced its XMS ProSeries memory modules, which attracted everybody’s attention mostly due to the extra-ordinary looks rather than to exclusive technical characteristics.

XMS ProSeries modules acquired a larger heat-spreader of new exclusive design. Besides that they are also provided with Memory Active LEDs (light emitting diodes showing the memory utilization). In fact, it is solely because of these exciting LEDs, that we decided to devote the whole review to the new Corsair XMS ProSeries memory modules.

Well, the new product line includes the following products:

In other words, Corsair XMS ProSeries offers only DDR400 and DDR500 memory modules with a shipment of two or only one per set. I am very thankful to Corsair Company for the opportunity to test a set of two DDR500 TwinX1024-4000PRO modules. So, today we are going to take a closer look at this product and see what the new Corsair XMS ProSeries family actually looks like.

Closer Look: Corsiar TwinX1024-4000PRO

TwinX1024-4000PRO set includes two non-registered DDR500 SDRAM memory modules 512MB each. These modules do not support ECC. Corsair targets this set with 1GB total storage capacity for high-performance systems with dual-channel memory controller. The memory modules included into the Corsair TwinX1024-4000PRO are based on 16 chips arranged as 32Mx8, i.e. these are dual-bank modules. Unfortunately, we don’t know exactly which chips are used in these memory modules, although we suppose that they are most likely to come from Hynix.

When you get hold of the new Corsair modules, the first thing that catches your eye is the larger size of the modules as well as the larger size of the heat-spreaders covering them. True, Corsiar TwinX1024-4000PRO modules are slightly taller than the regular ones: they are 4.5cm tall (compare with the 3.3cm by the regular modules), i.e. they are almost as tall as the Registered memory modules. You should always keep it in mind, because the size of these modules may not allow using them in certain PC cases.

The heat-spreaders installed onto the memory chips feature much bigger cooling surface. However, this surface has become bigger not only due to bigger height of the heat-spreaders. Now this surface is not flat but features about 1mm-ribs all over it. All in all, it led to the fact that the effective heatsink surface of TwinX1024-4000PRO modules turned 95% bigger than the effective surface of other Corsair heat-spreaders. Just like all the previous ones, the new heat-spreaders are stuck to the memory chips with conductive pads. Here I have to point out that it is not for nothing that the new memory modules acquired larger heat-spreaders. The modules do heat up quite tangibly during work.

If you look at the upper side of the heat-spreaders, you will notice another thing that distinguishes Corsair memory from many other similar products. There are two rows of 9 colored LEDs (green, yellow and red) for a total of 18. During work they light up depending on the intensity of memory addressing operations. For example in idle mode only four first green LEDs are lit up. If you start an application, however, something like a 3D shooter, all LEDs will light up. During regular work the LEDs are light up and go out all the time, so that the LED row starts looking more like the equalizer bar. Of course, LED indication like that is of no practical value.

Although those of you who have a case with transparent windows in it may love Corsair TwinX1024-4000PRO, because the blinking LED rows on the memory modules look really impressive. The only thing you should really worry about is to make sure that the HDD cables do not hide all this beauty from the viewer.

It is exactly because of this “color music” that the memory modules grew bigger in size. The additional space on the module PCB is definitely used for the LEDs electrical circuitry. Moreover, I have to express my concern about the influence of this additional circuitry on the modules stability. Of course, the LED indication circuit does add up more workload to the signal lines and power lines. So, since these memory modules work at a pretty high frequency this extra load certainly tells on the memory subsystem functioning. In fact, we will have a chance to check it out in practice later on, and now let’s continue with the features of the new TwinX1024-4000PRO from Corsair.

According to the official specification, Corsair TwinX1024-4000PRO can work at 250MHz (500MHz DDR) in dual-channel mode and have been preliminarily tested and approved for work in these conditions. The manufacturer guarantees the work of this module set at 250MHz frequency with the timing set to 3-4-4-8, which is considered to be pretty “mild” for most mainboards. The nominal voltage for these modules to work impeccably is 2.75V, according to the manufacturer.

In fact, the parameters listed in the modules SPD are slightly different from the claimed ones. The default timings for Corsair TwinX1024-4000PRO on the mainboards are 3-4-4-7. However, we find out even more exciting news if we use additional utilities to read the SPD parameters. Take, for instance, a well-known CPU-Z program:

CPU-Z version 1.19b
Memory Modules Serial Presence Detect (SPD)

Module #0
Memory type  DDR-SDRAM
Manufacturer (ID)  Corsair (7F7F9E0000000000)
Size  512MBytes
Max bandwidth  PC3700 (232MHz)
Part number  CMX512-4000
Max frequency @CAS#3.0  232MHz

Module #1
Memory type  DDR-SDRAM
Manufacturer (ID)  Corsair (7F7F9E0000000000)
Size  512MBytes
Max bandwidth  PC3700 (232MHz)
Part number  CMX512-4000
Max frequency @CAS#3.0  232MHz

As we see, for some unknown reason SPD of these modules indicates that their maximum working frequency is 232MHz. Moreover, it also says that this is not PC4000, but PC3700! Hm, this is a very upsetting mistake on Corsair’s part, which actually makes me a little doubtful about the high working frequency of this product. However, let’s turn to real benchmarks, which will help us to reveal the real performance advantages of Corsair TwinX1024-4000PRO.

Performance on i875P Based Mainboard

First of all, we decided to figure out with what memory timings and frequencies the new Corsair memory modules could actually work if used in an i875P based mainboard. Note that Corsair TwinX1024-4000PRO undergo all in-house testing for the ability to work at 250MHz (500MHz DDR) on this particular mainboard, and to be more exact on ASUS P4C800.

During this benchmark session we used the following system:

We tested the stability by running 3DMark2001 SE and 3DMark03 test sets, which load the memory subsystem really heavily. We also used a special Super Pi utility, which is capable of crashing down even the most stable and reliable systems.

The graph below shows at which frequencies, timings and voltages Corsair TwinX1024-4000PRO memory works stably enough in the above described system. During the test session we synchronously increased the FSB frequency and memory frequency (the maximum for our CPU was 280MHz) until the system turned unstable because of the memory subsystem errors. The AGP/PCI frequency was locked at 66/33MHz. The Performance Mode parameter was set in Turbo, and Performance Acceleration Mode – in Enabled position. However, the test results showed that none of these options had any effect on the top working frequencies of the tested memory modules.

Now let’s analyze the obtained results. As we see, with aggressive 2-2-2-5 timings, Corsair TwinX1024-4000PRO modules are unable to work at all (here I am talking about the frequencies of 200MHz and up). In fact, this is not at all surprising. In our article called Choosing Optimal Memory to Match Intel Pentium 4 Processor we have already pointed out that the memory modules capable of working at higher frequencies, and DDR500 definitely belongs here, cannot work with aggressive timings even in DDR400 mode. Now we see another proof of this point. Actually, for those users who are going to use their memory in DDR400 mode with aggressive timings, Corsair offers an alternative memory modules set: TwinX1024-3200C2PRO.

When we reset the timings to 2-3-3-6, Corsair TwinX1024-4000PRO starts working at pretty high frequencies reaching 225MHz with 2.75V Vdimm. The next qualitative improvement is observed when we change the timings to 2.5-4-4-8. In this mode the modules reach 256MHz working frequency. With the nominal 3-4-4-8 timings the result is about the same: the maximum working frequency for these modules reaches 257MHz. Note also that the 257MHz result is not that high at all: it is only 7MHz higher than the nominal. Although no one promised that Corsair TwinX1024-4000PRO will overclock well above the 250MHz, it is still a little disappointing that it wouldn’t. for example, the recently tested OCZ EL DDR PC-4000 Dual Channel memory managed to overclock to 261MHz. Probably Corsair modules are paying back this way for the additional circuitry used for the colorful LEDs.

Performance on i865PE Based Mainboard

Besides the tests with i875P based mainboard, we also undertook a few experiments with a mainboard on i865PE. To tell the truth, Canterwood based mainboards are pretty expensive that is why many users are most likely to go for their less expensive analogues based on i865PE. Especially since almost all the leading mainboard manufacturers enable PAT technology on their i865PE based products, making i875P and i865PE based solutions equally fast.

Our test system was configured in the following way:

The testing methodology remained the same in this case, that is why I suggest going over to the obtained results right away. I would just like to say that Performance Mode parameter was set to Turbo, and Memory Acceleration Mode – to Enabled. However, we saw throughout the test session that these parameters do not influence the maximum working frequency of Corsair TwinX1024-4000PRO in any way.

To tell the truth, I was shocked when I saw these results. It turns out that Corsair TwinX1024-4000PRO works much worse on i865PE based mainboards. I ran all the tests anew, however, the result didn’t change. Corsair TwinX1024-4000PRO failed to exceed the nominal working frequencies even when I replaced the ASUS mainboard with an ABIT IS7 and disabled Game Accelerator technology. So, it means that the mainboard has nothing to do with it. At the same time, DDR500 modules from OCZ, EL DDR PC-4000 Dual Channel, show absolutely identical overclockability in both: i875P and i865PE based systems. So, you should definitely keep in mind that Corsair TwinX1024-4000PRO works in i865PE based mainboards slower than in more expensive i875P based ones. And it is probably connected with those LED circuits laid out on the Corsair’s PCB, while i875P is capable of standing much higher load on its signal lines because it uses specially selected faster dies.

This way, we wouldn’t recommend using the new Corsair XMS ProSeries memory modules in systems with an i865PE based mainboard.

Application Field

Before we pass over to the actual analysis of the performance boost you can get due to the new Corsair TwinX1024-4000PRO memory modules, let’s try to figure out what would be the best application for them. As we have just seen, these memory modules can’t work with aggressive memory timings, that is why their major advantage is the higher working frequency. This feature is valuable if you are overclocking your CPU and tend to overclock the FSB and memory frequency synchronously. Besides, it doesn’t make any sense to use Corsair TwinX1024-4000PRO at 200MHz or close, because other memory modules (such as TwinX1024-3200C2PRO) will surely provide much higher performance boost due to lower latencies.

However, 257MHz frequency, which we will be able to achieve with the modules we are testing today, is not that high at all: many Pentium 4 processors can work at a much higher FSB frequency. For example, you can easily overclock a Pentium 4 CPU with 800MHz bus up to 3.5-3.6GHz. This way, it makes much more sense to use Corsair TwinX1024-4000PRO when you overclock your CPU with a 14x multiplier, i.e. during Pentium 4 2.8C overclocking. In this case, increasing the FSB frequency to 250-260MHz allows reaching about 3.5-3.6GHz CPU frequency. The CPUs with lower multipliers are most likely to be restricted by the maximum memory frequency thus requiring the lowering dividers. However, when you apply lowering dividers the memory frequency drops down to around 200MHz, which means that it would be better to use DDR400 with lower latency.

When you overclock a CPU with the multiplier above 14x, the memory cannot reveal all its potential, because the FSB frequency increase will be slowed down by the CPU frontiers.  In other words, Corsair TwinX1024-4000PRO, as well as  any other DDR500 memory, appears to have very narrow application field.

Now let’s still try to find out what the benefits of Corsair TwinX1024-4000PRO are when used in the most favorable conditions, that is during Pentium 4 2.8C processor overclocking. Here we will compare the performance of two systems:

Note that the result of this testing is not predetermined at all. The thing is that Corsair TWINX1024-3200LL working at 205MHz can allow 2-2-2-5 timings, and in order to make our Corsair TwinX1024-4000PRO work at the desired 256MHz, we will have to use much worse timings: 3-4-4-8.

The test systems in this case were configured as follows:

Besides, for a more illustrative comparison I also added the results obtained on similar systems with faster processors of the Pentium 4 family: Pentium 4 3.2GHz and Pentium 4 Extreme Edition 3.2GHz.

In synthetic memory benchmarks Corsair TwinX1024-4000PRO allows to get about 6-7% performance advantage over the rivals. However, these are synthetic benchmarks, don’t forget about it, and the performance here mostly depends on the bandwidth of the bus between the CPU and the memory. In real applications the latency is also very important, which you can clearly see from the results we obtained in real apps:

Well, the situation doesn’t look very good for Corsair TwinX1024-4000PRO, to tell the truth. The advantages provided in synchronous mode is pretty stable and hardly exceeds 1%. Asynchronously working DDR400 modules with aggressive memory timings ensure about the same performance, and in some tests, like WinRAR or Unreal Tournament 2003, they even provide a significant performance improvement. This way, the resume is not very positive: using Corsair TwinX1024-4000PRO in today’s typical systems doesn’t have any worthy advantages.


Well, I started out a regular memory review today, however, it looks as if I got some pretty exciting results in the long run. And these results make sense not only for the memory modules tested today, but for the whole bunch of similar products coming into the today’s market.

First of all I have to stress that as we have seen again, using overclocking friendly DDR500 memory modules in regular systems is none other but tickling your vanity, without any actual reasons. DDR400 SDRAM with lowering coefficients and lower latency provides about the same performance level even in the worst case. We have already mentioned it in our article called Choosing Optimal Memory to Match Intel Pentium 4 Processor. And today we saw another piece of evidence proving this point.

Secondly, if you made up your mind to get the overclocker’s DDR500 SDRAM, then Corsair TwinX1024-4000PRO modules  might not be the best choice for you in terms of their functional characteristics. There are more stable and faster memory modules in the today’s market. You are free to choose from a few alternatives by the same Corsair or OCZ. Besides, Corsair TwinX1024-4000PRO doesn’t work that well with i865PE based mainboards, that is why we would warn you against using this combination in your system.

Of course, the LED indicator system used on Corsair TwinX1024-4000PRO deserves all the praise. The “memory activity LEDs” will become a really nice feature of your system case. However, when you get your XMS ProSeries modules you should keep in mind that nicely blinking LEDs harm your system reliability.

So, summing up, I can say that Corsair TwinX1024-4000PRO appeared to be a pretty fun thing, which will find its place in overclockers’ systems based on i875P platforms. However, quite a few drawbacks we discovered during the test session prevent me from calling this product the today’s best choice.