Armed with a good Canterwood board, and an overclocking friendly Pentium 4 (the 2.4GHz "C" is my personal favorite), overclocks of 250FSB are not unheard of. Adjustments to PC3200 ram typically needs to be made to the memory and CPU ratios to reach these FSBs, hence the popularity of PC4000 modules. It's no secret that a 1:1 ratio will net the best performance, but once we pass 250FSB (the maximum rated clock speed of PC4000 modules), it gets tricky. Yes, it can be done, but depending on your ram, your settings, and the position of the moon, your results will vary.

Corsair recently sent us a couple of sticks of their TWINX1024-4400 ram. As with their past TWINX kits, these are a couple of their XMS series ram, tested in pairs and validated for a Dual Channel environment. What is new about this kit is the modules are their new PC4400 (275MHz, DDR550). Why faster ram? Simple... why stop at 250FSB if your setup can do more? As I've mentioned earlier, quality PC4000 can do in excess of 250FSB, but the PC4400 kit is made to do it.

With the Corsair TWINX1024-4400 we'll be reviewing today, we now have an opportunity to run synchronous (1:1) at 275MHz. Can we go beyond that? We're definitely going to try.

Specifications

Part Number	Speed	Size	Package	CAS Latency
TWINX1024-4400	550 MHz	1GB	2x184 DIMM	3-4-4-8

You can view the full specifications in this PDF, but what you need to know is the modules are validated with an ASUS P4C800-E. I have gotten similar overclocking and performance results with an ABIT IC7-MAX3, though I was not able to boot my MSI K8T Neo (K8T800) using these modules. I'm still investigating this further, but seeing how Athlon 64 and K8T800 overclocking is still a problem, I wouldn't have recommended anything past PC3700 for those setups anyways.

The ram modules arrived in a hard plastic case, with each ram module fitted in the clear plastic shell. The only reason I'm pointing this out is because there should be no confusion in what you're getting. You have a clear view of the ram, and the labels (indicating the type of modules), and the packaging is heat sealed. This will cut down on fraud or repackaging that is unfortunately a real problem in the market. It should be pretty obvious to the buyer if the package has been tampered with.

Like some of the past Corsair XMS modules we've reviewed, their ram modules are encased in black heatspreaders (Platinum coloured ones are available). I'm preaching to the choir here, but heatspreaders have yet to convince me that they effectively cool ram to the point where it will make a difference in overclocking. They do look swank though, and I guess any cooling included won't hurt. What I was told by a marketing rep was that heatspreaders will reduce EMI since it shields the ram, but I don't have any quantitative proof of that.

A closer look at the modules, and we can see the silver sticker letting you know the specs of that stick of ram. We can see that it's a 512MB stick, rated at 550MHz, with ram timings of 3-4-4-8. As many enthusiasts know, tighter timings (say 2-2-2-6) result in better performance, but as memory speeds increase, it is extremely difficult to maintain stability with such low timings. To be honest, 3-4-4-8 is pretty good all for 550MHz. Sure, it can be better, and we'll see how we can do with some tweaking.

Stability Testing Procedure

We're going to be doing a few things differently today than we've done in the past. I was able to acquire a RAM Stress Test Professional (R.S.T.) Pro2 card as a loaner for stability testing. In the past, we've used MemTest, but I never found the software to be of much value with the latest ram modules. Also, we've hit some fantastic overclocks, and ran them with stability for benchmarking, but the truth is, extended periods of OCing caused some quirky system behaviour after a few days.

How the R.S.T. Pro2 works is it installs into a free PCI slot, much like any standard PCI card. You have to take care in installing it correctly though (there is a sticker that indicates the proper orientation) or you will kill your motherboard in less than five seconds. Once the card is installed, it bypasses the OS completely, loading a proprietary OS and software package (embedded on the card itself), and allows you to perform stress and performance benchmarks without the Operating System's memory footprint, memory resident programs, or drivers interfering with the memory installed.

Once the card is installed, the system will POST (you can edit memory settings as usual in the BIOS during this step), and the R.S.T. Pro2 takes over. Unfortunately, because of time constraints and having to return the card, I only managed to test for stability of the TWINX PC4400 and several other modules. I can certainly see the value of this tool though, as the testing options outside of stress testing is quite impressive.

Overclocking

With the R.S.T. Pro2 in place, I proceeded to hammer away at the TWINX PC4400. We tested the TWINX at seven different speeds and timings... 250MHz @ 2.5-4-3-5, 250MHz @ 2.5-4-3-6, 250MHz @ 3-4-4-8, 275MHz @ 2.5-4-3-6, 275MHz @ 3-4-4-8, 277MHz @ 3-4-4-8, and 288MHz @ 3-4-4-8. At 277MHz and 288MHz, we needed to bump the voltage from the default 2.75v to 2.8v. These were our results:

Speed	Result
250MHz @ 2.5-4-3-5	Fail
250MHz @ 2.5-4-3-6	Pass
250MHz @ 3-4-4-8	Pass
275MHz @ 2.5-4-3-6	Fail
275MHz @ 3-4-4-8	Pass
277MHz @ 3-4-4-8	Pass
288MHz @ 3-4-4-8	Fail

I should point out that we tried different speed and timing variations outside of what you see above, but the numbers we've presented were FSB speeds Windows was able to POST at. However, as you can see, R.S.T. Pro had a thing or two to say when it came down to stability.

For fun, I grabbed our Corsair PC4000 ProSeries, and bumped it up to 290FSB, which it had handled in the past. Given what we've learned today, I guess I wasn't too surprised to see that it failed the R.S.T. Pro tests, despite it being fairly stable in Windows. We also tested several other ram modules using this test method, but I'll sum it up later on.

Test Setup

ASUS P4C800-E: Pentium 4 2.4C, 2 x 512MB Corsair TWINX1024-4400, ATI AIW Radeon 9800 Pro, 80GB Western Digital, Windows XP SP1, ATI Catalyst 3.10.

Test Software for both platforms will be:

SiSoft Sandra 2004 Memory
PiFast
TMPGEnc AVI-to-MPG Encoding
Unreal Tournament 2003
Splinter Cell

Unfortunately, I do not have any 512MB/PC4400 sticks of competing products. We will be presenting benchmarks at 250MHz @ 2.5-4-3-6, 275MHz @ 3-4-4-8 and 277MHz @ 3-4-4-8 on the P4C800-E, all in Dual Channel mode. I will not be displaying 200MHz numbers, which I will explain why at the end of the review. The CPU and Memory ratio will be 1:1.