Concluding thoughts
We've attempted to demonstrate why a faster FSB and associated synchronous memory speed, ceteris paribus, will pay performance dividends. That's one of the main reasons why both Intel and AMD made the consumer-level jump to a 200MHz FSB. Raising the Front-Side Bus further, therefore, is a good thing for those chasing performance. Corsair, like most others, used to push its premium memory on low-ish latencies. That situation seems to have been reversed recently, especially in the quest for ever-faster speeds. We noticed the trend with its XMS3700 line. The XMS4000, in both its standard and glorified LED incarnations, also exhibited high-ish latencies of 3-4-4-8.XMS4000, DDR500, or 250MHz FSB with synchronous RAM speed, was destined for Intel's dual-channel chipsets that showed an aptitude for high FSB running. There was a definite need for high-speed RAM and Corsair filled it. It's now gone that much further with RAM ratified at a blistering DDR550 speed. The problem is not one of ensuring RAM is up to the job, it's one of ensuring that the CPU (locked, presumably) and motherboard can handle 275MHz FSB. Therein lies one the XMS4400's chief attributes and weaknesses. If you, the enthusiast, can absolutely guarantee that your setup can hit 275MHz FSB without a murmur, Corsair's latest ultra-high speed memory is almost the perfect partner. Our test TwinX pair hit the rated mark with ease. Overclocking it was fraught with difficulty. It's difficult to draw the line between FSB failure (motherboard or CPU) or RAM failure. Our testing halted at 283MHz FSB (DDR566). It appeared to be a motherboard limit as the DRAM's voltage was left untouched. On the other hand, if 275MHz FSB is unknown territory, Corsair's XMS4400 TwinX is pure overkill.
Like most enthusiast-orientated hardware, whether it's worth it or not depends on just how well you can make use of it. Corsair's XMS4400 TwinX 1GByte memory is aimed at the enthusiast with ultra-deep pockets, and one who doesn't want system RAM to become the limiting factor, assuming synchronous FSB running is the aim. We can envisage it in a system that uses a refrigerant-cooled P4 at ludicrously high FSB speeds. What it has in common with most other high-speed RAM is the inability to run at low latencies. 2-2-2-6 was a no-go at DDR400 speeds, and anything other than SPD timings was prone to the occasional failure. To steal and manipulate a film line, it's RAM that's manufactured for a single purpose; to go extremely high on the MHz scale, but do so with relaxed latencies.
In summary, Corsair's XMS4400 TwinX 1GByte memory pack will appeal to a very select, niche market. Priced at over £300 it certainly isn't cheap. Recommended if your setup can make the full use of it - just ensure that it can before you part with a large chunk of cash.
- Assuming you can use its potential
