Callahan wrote:It will work with pc2-4200f. Tested on my xw with 1066, 1333 FSB. Not sure with 1600FSB, these i haven't tested.
Dual lga771 is nice rig but performance of fbdimm is awful.
The performance of FBDIMM is not awful. It's a different technology that apparently you don't understand.
FBDIMM is server grade RAM. Server grade RAM is designed for low error rates vice raw speed.
The throughput might be slower on paper but it's of higher quality (less errors in it) so the CPU does not have to spend as much time repeating data transfers that were corrupted as it does on a computer with consumer based RAM.
FBDIMM is unlike previous technologies in that the ECC is internal (on the module only). It is not between the CPU and RAM.
That allows all the errors to be fixed 'in RAM' (which reduces CPU-RAM loading) and why it runs slower -on paper- than consumer RAM.
Consumer RAM might be faster -on paper- but it has the overhead of the CPU having to fix errors that would have been taken care of in RAM on a FBDIMM system.
IOW:
FBDIMM is slower with fewer errors that require repeating operations.
Consumer RAM is faster with more errors that require repeating operations.
At the end of the day there is no humanly perceivable difference between FBDIMM and consumer RAM of otherwise similar specs.
It seems hypocritical to me that you are criticizing FBDIMM performance at the same time you are recommending PC2-4200F which is the wrong spec RAM for the system and will underclock it by about 25%.
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