A few weeks ago on September 15, 2003 Corsair released a new line of memory (XMS Pro) that was aimed directly at the heart of the enthusiast and DIY (Do-It-Yourself) crowd. The new modules have been altered, but the changes do not have an impact on performance. This is good news as all the XMS 4000 owners don't have to worry about a faster product coming out. The main changes are the memory activated LED's and a newly designed heatsink that looks pretty effective due to the increase in size and the fact that it is now bonded to the memory IC's. (used to be attached via thermal tape) The new cast aluminum heatsink has small ribs in it that Corsair claims increase surface area by 95% compared to standard aluminum spreaders, which may or may not increase the cooling ability of these toasty 500MHz modules. They do get warm!

As you can see in the photo above the overall size of the module has greatly increased due to the addition of the LED's. It is now much taller, standing at 1.75 inches in height which could be an issue for some SFF (Small Form Factor) users, but not from what we have seen so far from the multiple SFF systems we have in house.

Let's go in more detail and look at the features!


The XMS4000 Pro TwinX DDR Modules came in a recyclable plastic box that contained the first installiation manual that we have ever seen Corsair put together. If you need installation help with DDR500 memory you are best off staying away from your system, but Corsair went the extra mile to include directions!

An important factor in buying memory is the warranty. Corsair's memory products carry a lifetime warranty. This means that Corsair products are guaranteed to operate, as specified by their datasheet and in the operating environment for which they were intended, for the life of the product.

Some of the new features on the modules are the 18 LED's per module that can be found in three different colors (green, yellow, red) which show the level of memory activity. The image below shows low activity on the left, some activity in the middle, and full activity on the right.

I must say that it was fun to watch what your memory is doing. The above photo was taken with the lights on and no flash while testing the memory on an MSI Springdale 865PE Neo2 motherboard. Being a professional review site we try to use memory on as many boards as possible to see if we can identify any issues between brands and chipsets. Below is a shot of the final test system and shows how your case will look when the lights go out.

The memory we are testing today are TWINX matched memory pairs that have been specifically designed for motherboards using chipsets with dual memory channels. Current two-channel chipsets include the 875P ("Canterwood") and 865PE/G ("Springdale") from Intel, the nForce2 Ultra 400 from Nvidia, and the new nForce 3's. Corsair tests the DDR500 modules in an Asus P4C800 motherboard and the modules are programmed to JEDEC 3200 (DDR400) values There is no official standard yet for DDR500, but all of the manufacturers seem to be using the 875/865 chipset motherboards to verify their high-speed performance. All Corsair memory comes with a sticker that tells you exactly what your memory is rated for.

Key Features:

Moving on to the benchmarks, let's see how this ram performs!

Testing Methods:

How Do We Define Stable Memory?

Have you ever run across a review website that reviews a product and shows a couple amazing scores and gives it an award? Sure you do as most review sites do just that, but how stable was it? I would be willing to bet that most sites don't know what stable memory is and therefore give fairly inaccurate results. Yes, I hate to break the news, but there is more than just running a memory bandwidth test and calling memory stable.

Ever wonder what the memory companies use to test their modules? So did we, and we found out that they use the RAM Stress Test Professional (R.S.T. Pro). Well, one thing led to another and we went out and picked up the R.S.T. Pro to use in this review. What is the R.S.T. Pro? It is a Self-Booting, Operating System Independent memory diagnostic card for exercising and validating RAM. The R.S.T. Pro runs all tests in protected mode which can completely and thoroughly test up to 64 gigabytes of memory. This utility provides users the options of running sophisticated test patterns to detect hard to find memory errors, which are not detected by other test software.

While using the R.S.T. Pro we were able to find memory errors that other testing methods could not find or reproduce. Since we want and encourage our readers to follow up our testing on their own we also used the free testing program called Memtest86 which is a stand alone memory test for x86 architecture computers that boots off a floppy disk. We will go ahead and show the actual errors detected on Memtest86, as it is free and everyone can check into it.

We would also like to note that the errors found in test 5 and 8 do not mean the memory is faulty. As the Memtest86 homepage states: "Errors from this test [5 & 8] are not used to calculate BadRAM patterns."

We also ran Prime95 while running loops of 3dmark2001 for a minimum of six hours to make sure that under hours of stress and heat buildup that the modules were truly stable.

We considered memory stable when it was able to run 1 extended pass of Memtest86, six hours of Prime95/3dmark testing and without locking up while running all tests on the RSTPro. Many consider if any errors are found using the RSTPro or Memtest86 testing methods the memory has failed. Since 3 of our 6 modules would have failed from testing the modules at default timings we kept going.

By this combination we feel that this review is contains some of the most accurate testing ever completed in terms of memory stability. Sure, not everyone will agree with our stability testing methods, but we can try to make the majority happy!

Stability Results:

Sure we could get our Corsair XMS Pro modules to run some benchmarks at 534MHz, but when put through some stability stress testing we found the top end of the memory to be 516MHz at default timings and voltages. Once we dropped the timings we found the max to be 514MHz. These are pretty good numbers for having this memory at aggressive timings beyond 500MHz.

Now let's take a look at performance testing!


Our Test System:

Memory Used:

Driver Versions:

Testing Procedure :

All testing was done on a fresh install of Windows XP Professional build 2600 with Service Pack 1A and DirectX 9.0b. All benchmarks were completed on the desktop with no other software programs running. No overclocking was done on the video card unless noted. Our testing processor was an unlocked Intel Pentium 4 3.0C. Our testing was done at 250x12 = 3.0GHz with H/T enabled. We did disable the audio, USB, Firewire, and lan features found in the BIOS menu for all the testing competed during this review.

All testing was completed at 2.8Vdimm unless otherwise noted!

Now for the results!

Memory Performance:

Results: At default timings the Corsair XMS Pro performs equally with it's 500MHz counterpart. This is correct since both modules use virtually the same PCB design and IC's. The numbers should be failry consisent and our results showed this to be true. Also included in the above graph on the fair right column are the results from testing at agressive timings at the specified DDR-500 speeds. An increase of only 0.41fps was observed in Comanche 4 by lowering the timings. At these memory speeds we can tell that memory bandwidth is not the major limiting factor.

Now let's look at overclocking at loose timings:

Results: We found that both the Corsair TWINX1024-4000 and TWINX1024-4000Pro memory kits maxed out at the same exact speeds! Again, with the similar PCB design we were not expecting to see bigger numbers as this memory is aimed at the gamers and users who like to show off their computer!


Corsair has been a huge player in the American memory market for a number of years now and has successfully released a new line of memory that assures their place in the performance memory market for many more years. Why is it that Corsair plays a leading role in the memory industry? The answer to that is simple, they design and make their own products. If the consumers what LED activity lights on their memory Corsair goes to the drawing board and designs it from scratch. Many other companies can only wait for other companies to manufacture it for them so they can just slap their heat spreaders on it!

The Corsair XMS PRO series was launched just for gamers and people who mod their pc's by a company who listens to their customers! We also found that adding LED activity lights had no impact on performance even though some might believe that they will decrease performance! The Corsair XMS 4000PRO series is on par with Corsair XMS 4000, which took top grabs from our site a couple weeks ago when we published a 6-way DDR 500 memory round-up. Since it performs equally with the XMS 4000 series this memory is highly recommended for enthusiasts or any user looking for the best in style and performance.

With the launch of XMS 4000 memory Corsair answered the call of enthusiasts by releasing a product that eliminates the worry of having too little memory bandwidth! Now with the XMS 4000Pro series we have a totally brand new Corsair product that eliminates the memory bandwidth issue and adds style and elegance! On top of all that don't forget that Corsair is now bonding their heat spreaders for improved thermal transfer of heat and has a much larger surface area to help dissipate heat! Honestly how much better does it get? If you are looking for Xtreme memory speeds with additional eye candy features then look no further as the XMS 4000Pro Series has arrived!

If this line of memory does not suit your needs check out and see if Corsair has any memory for your individual needs!

Editor's Choice Award