Last year, Corsair released their TWIN2X-8000UL which at the time was their highest frequency part. While it wasn't officially at the "1066MHz" FSB threshold of enthusiast motherboards at the time, it was close enough. With chipsets from Intel, NVIDIA and others supporting 1066FSB, and a year later, a frequency of 1GHz isn't quite enough.

Today we'll be looking at Corsair's TWIN2X512-8500 memory. Supporting 1066MHz out of the box, users with 1066MHz CPUs will be very happy to finally run with CPU and memory synchronically right off the bat. While we received a 1GB kit, those of you working with a lot of memory intensive apps or games will want to consider the 2GB version of the memory kit.

The Corsair TWIN2X-8500 Memory Kit

Part Number	Speed	Size	CAS Latency
TWIN2X512-8500	1066MHz	1GB	5-5-5-15

The ram modules arrived in a hard plastic case, with each ram module fitted in the clear plastic shell, thus 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). The modules are built using hand picked Micron D rev ram, allowing Corsair to build modules that meet the expectations enthusiasts set.

As with most Corsair XMS modules we've reviewed, this kit features memory modules encased in black heatspreaders. The heatspreaders will move some heat off the memory modules as well as shielding the memory from your computer's internal EMI. The heatspreaders are quite warm to the touch, so overclockers may want to think about additional cooling for the area. IF you're water-cooling, we think this is a requirement.

A closer look at the modules, and we can see the sticker letting you know the specs of that stick of ram. For this particular kit, each stick is 512MB, model XMS2-8500 running at 1066MHz. The latency rating is 5 (CAS Latency) - 5 (RAS # Precharge) - 5 (RAS to CAS Delay)- 15 (RAS# Activate to Precharge). It's not displayed, but the Command Rate of these modules is 2T. These timings are programmed into the SPD at 800MHz, and on our ASUS P5WD2 Premium, we needed to manually set it at 1066MHz. Corsair has validated the memory using an ASUS P5WD2-E Premium, and highly recommend users to use the same board, or the ASUS P5WDG2-WS or ASUS P5WD2 Premium boards to get the most out of the kit. In our experience, ASUS boards are generally some of the better overclockers, so we're in agreement here, though we think any Tier-1 board maker is worth considering as well.

Stability Testing Procedure

The RAM Stress Test Professional (R.S.T.) Pro2 card is a mainstay in our memory tests.

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.

With the R.S.T. Pro2 in place, I proceeded to hammer away at the TWIN2X512-8500 using an ASUS P5WD2 Premium and Intel 840EE with its multiplier manually set to 12.

We tested the TWIN2X at five different speeds and timings, all at 2.2v.

Speed	Result
DDR2-764 @ 3-3-3-9-2T	Pass
DDR2-805 @ 3-3-3-9-2T	Fail
DDR2-805 @ 3-4-4-9-2T	Pass
DDR2-1000 @ 4-4-4-12-2T	Pass
DDR2-1070 @ 5-5-5-15-1T	Pass

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.

Test Setup

ASUS P5WD2: Pentium 4 840 Extreme Edition, 2 x 512MB Corsair TWIN2X-8500, MSI NX7800GTX, 160GB Seagate SATA 7200rpm, Windows XP SP1.

The memory will be tested at DDR2-805 @ 3-4-4-9-2T, and DDR2-1070 @ 5-5-5-15-1T. We will also be throwing the TWIN2X-8000UL into the mix at 5-4-4-9-T1.

Sisoft Sandra 2005 Memory

I've argued this a few times, but I'm still pretty much committed to the fact that tight timings are better than high frequencies. This is to an extent of course, but here, at 800MHz, the TWIN2X-8500 puts up its best numbers.

PiFast

805 @ 3-4-4-9-2T is netting us the best results here in our standard PiFast test.

Doom 3

Unreal Tournament 2004

In our gaming tests, we see the higher frequencies making more of a statement here.

Final Words

Overclocking was good considering we're already running at a pretty high speed. Of course, underclocking is an option if you're interested in running at lower timings. The ram does get pretty toasty, even at stock speed, so make sure the area around the ram isn't too cluttered. We do think an additional fan in the area is a must have if you're water cooling your computer.

The Corsair TWIN2X-8500 is a strong performer at both high frequency and low latencies. Basically, depending on your needs, the ram can easily switch between the two options. To be truthful, the main market for this memory is going to be users with 1066MHz CPUs so that they can run their memory 1:1. That said, I think overall you'll see better numbers if you can tighten the timings at the expense of a slightly lower clock speed. In other words, if you're the owner of an Athlon AM2 or any 800MHz FSB Pentium CPU, you're much better off opting for a low latency DDR2 kit. However, if a 1066FSB CPU is in your future, it may be worthwhile keeping an eye out for the TWIN2X-8500 since it can be ran at lower frequencies if you need to.

If you have any comments, be sure to hit us up in our forums.

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