Is choosing Opteron(s) or Xeon(s) over a Core2 Duo 6850/Quad 6600 the better choice?If so, what models/combinations are recommended?I'm pretty unfamiliar with Opterons and Xeons altogether, so I have no knowledge wheter two of them are needed in two sockets or not to not loose any feature.Andreas

I started buying Xeon systems about 4 years ago and I know a little about them from practical experience.I have been very pleased with my Xeon systems. They give excellent performance without overclocking. Mine are Dell Precisions: they have always been completely reliable.However, frankly, Xeons really are not the most suitable processors for FSX. Here's why:The main advantage of Xeons is that Intel typically releases them with higher clock speeds than its consumer models INITIALLY. Thus, for a [very high] price, you can buy a short-term advantage in clock speeds until the consumer models catch up. For example, you can now buy (or at least order) quad core Xeons running at 3.2GHz.However, the "Xeon" brand is ultimately just part of Intel's irritating but hugely profitable tactic of segmenting the market into tiny slices. There is not much difference technologically between consumer processors and Xeons (assuming they belong to the same generation): the consumer chips are really just Xeons that have been crippled by having various functions disabled. The most significant difference is that you can only put 1 consumer CPU into a computer, while Xeons can be installed in 2s or 4s. This is much less of an advantage now that consumer processors come with more than 1 core. The consumer processors invariably catch up with and eventually overtake the Xeon clockspeeds.The chipsets for Xeons are also different. The main difference is that chipsets for Xeons can accommodate much more RAM than those made for consumer processors (generally, about 64Gb). In fact this is generally the best reason for buying a Xeon system. But the price of being able to address as much as 64Gb of RAM is that all the RAM in a modern Xeon system must be fully-buffered (at the moment, anyway). This slows it down significantly compared with the fastest consumer RAM: you just cannot run RAM as fast in a Xeon PC as in a consumer system. For example, the fastest RAM for a 5100 generation Xeon is 667MHz, but with relatively unfavourable steppings compared with consumer RAM. The very latest Xeons can take 800MHz RAM, but again the steppings are relatively unfavourable. Another difference is overclocking. While I believe it is possible to buy overclockable motherboards for Xeons, this is very much a minority interest compared with the market for such motherboards for consumer processors. Two or more cores help, but clockspeed is the key to performance in FSX. The relative difficulty of overclocking Xeons is therefore a significant factor.Overall, you will be better off - both financially and in terms of performance - with a high-end overclockable gaming system using a consumer processor. To squeeze the last ounce of performance from your PC, invest some extra cash in fast 15k RPM SCSI/SAS drives: these really do make a noticeable difference and if you are willing to splash out on professional-grade hardware, they will be a far better long-term investment than paying a premium for Xeons.Tim Morshead

Thank you Tim for your explanations.Andreas