Inspection and comments
The TWINX range of memory kits arrive in Corsair's customary XMS packaging. There are two new 'features' with this particular range of memory. Firstly, you may be able to see the full name of this module in rather trendy hologram labelling system above, CMX256A-3200LL, to give it its full title. The PC3200 reference, as you may well know, simply infers that the module will run at PC3200 (DDR-400, 200FSB, take your pick) speeds. Nothing that amazing there as we've seen PC3200 speeds for some time now.
The LL, though, is what's a little different this time around. If you read my XMS3200 C2 review a little while ago, you'll know that whilst running at the then lofty speeds of DDR-400 with a CAS Latency of 2 clocks (that was impressive for mid-2002), the other timings left just a little to be desired. Quoting the industry-standard method of describing timings, it ran at 2-3-3-6-T1. The numbers refer to CAS latency, RAS precharge, RAS-to-CAS delay, RAS active to precharge, and command rate. Without tying you up in technical explanations, the numerically lower each setting, the better it will perform, generally.
The low latency name is deserved on this count as the module runs at a 2-2-2-6-T1 rating. We who like to think of ourselves as enthusiasts pushing back the boundaries of system performance always like to see 2-2-2 timings specified as standard. That's the hallmark of aggressive and confident memory. Being a memory enthusiast myself, seeing PC3200+ speeds with 2-2-2 timings is always reassuring.
Most motherboards recognise system memory from its pre-programmed SPD (Serial Presence Detect). Corsair have backed up their low latency claims by specifying the 2-2-2-6-T1 SPD for this module. That effectively means your motherboard will apply the tight timings naturally on boot-up. You are, of course, free to change them manually in most cases. Running a single module in a nForce2-based motherboard with a 333FSB (166FSB DDR) AMD XP2700 in the drivers' seat forced the board to run SPD timings of 2-2-2-5-T1 at the CPU's native 166FSB (PC2700 speeds). I'll bet you that well-known system integrators featuring XP2700 CPUs in their machines won't give you those RAM timings by default.
Speaking of the nForce2, it's no secret that it works best in dual-channel synchronous mode. Having two channels nominally doubles the amount of precious bandwidth you have on offer. The extra amount that the stock XP2700 CPU can physically use is significantly lower than the 5.4GB/s potentially on tap. In terms of memory, though, more is almost always better. The obvious problem facing those wishing to run tight timings on a dual-channel motherboard is compatibility. Having to run two modules, especially with low latencies involved, is inherently more difficult than running just one. To ensure that the compatibility problem is negated, Corsair, and this is the second so-called feature here, have bundled two pre-tested modules together as a kit. These matched modules are guaranteed to work flawlessly as a pair, thereby taking the guesswork out of the equation. The validation comes from physically testing pairs of modules in an Asus A7N8X nForce2 motherboard. Those that run well with their neighbours are packaged together under the name of TWINX.
So, just to recap, the TWINX range of memory modules offer high native speeds, low latencies (always a good thing in my eyes), a very aggressive pre-programmed SPD to ensure your motherboard applies the best settings, and, importantly, the verification that the pair of modules will run flawlessly as a pair in a dual-channel environment. The dual-channel verification interests me the most here. We'll have to investigate if it has some real merit to it a little later.
