I originally had the ASUS P5W DH DELUXE/WIFI-AP LGA 775 MB and a pair ofCORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X2048-6400http://www.newegg.com/Product/Produc...82E16820145590It was running at 378.4Mhz (lower than the 400) speed at 5-6-6-18-24 (CPU-Z) at 2.1vAnd everything was fine. So now I added 2 more sticks of the same.. Identical sticks making it 4Gig. But Its giving me grief. machine screeches and freezes and what not.I know the sticks by themselves are good,,cause when I swaped the 2 gigs with the new 2gigs. they run fine by themselves.If I reduce the memory frequency considerably, it seems to be ok or better. when I run 3Dmark test and stuff..overall benchmarks are very slow/low. What do I do? any ideas.Should I return this and get 2 x 512 making it 3Gigs maybe even a faster memory. would that help. I would be happy with 3 Gigs as long as its not slower than my 2 Gig setup.Manny

Manny,When I added my extra 1G memory I was no longer able to achieve the same overclock at the same CPU and memory voltage settings. I used to be able to run 3.5GHz at 1.4625V vcore and +0.1V memory when I had 2G and now I have to run at 1.5V and +0.2V memory to give me total stability. I guess it's the price you pay for filling those memory slots.Gary

This is what I got from Corsair support forumQuote:"I would just run the two 1.0 Gig modules for best performance but with this MB if you install more than two modules I would suggest DDR667 or DD533 on the memory.__________________Ram Guy:(

The only reason I wanted to addmore memory was that silly MD80 that eats up so much memory for its 2D textures to run in FSX.I think..I am going to return that memory. Its way too slow for some extra memory. not worth it. This is ridiculous.Manny

XP or Vista? If XP, try 3 gig, not 4.Allcott

I know for some boards in the past, that was very true, and may still be the case. Any time you ran with all mem slots filled, the board did not like the higher settings.I am not familiar with your motherboard to know if this is the case for yours, however.Are you running Vista?RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

Rhett, Alcott.I am running XP. I don't believe I can go Vista. Vista needs memory..and I can't spare any from my 2Gigs if I can't any more memory.I never knew...that ASUS MB (and other MBs) has a limit of 2 Gigs without drastically making the whole machine a dog.Manny

Actually its 3 GIg and is mentioned in the manual I have yet to see FSX go higher than 1.6 gig of memroy usage thats with most settings on high so i doubt that 3 gig would make any difference anyway.

At what command rate are you running the memory? Try 2T instead of 1T.Regards,Jim Karn

I had a bit of a problem also. I found that it's not good to mix em up. What I mean is according to Corsair the memory is matched up when it's packaged. I guess different lots have slightly different timings?Anyhow I plugged the first set into slots A1/B1 and the second into A2/B2 making sure the lot numbers were the same. That worked. The twinx xms2 6400C4 should work fine at 4-4-4-12 2T. The BIOS default setup gave me 5-5-5-18 2T.I had to go into the BIOS and set everything to Manual, I could then set all parameters the way I wanted.Here are the correct settings for your board:Motherboard make and model: Asus P5WD2 or M2N32-SLI Premium/DeluxeEach pair is tested and packaged together using the following settings:AI Over Clock Tuner: ManualCPU External Frequency: Manually set to 200MHzDDR2 SDRAM Clock: Manually set to 800MHzPCI Express Freq: AutoPCI Freq: 33.33Performance Mode: StandardDRAM Timing Selectable: ManualSDRAM CAS Latency: 4TSDRAM RAS to CAS Delay (tRCD): 4TSDRAM Row Precharge (tRP): 4TSDRAM Active to Precharge Delay (tRAS): 12TSDRAM Write Recovery Time: 5Write to Precharge Delay: 15 (If it's Listed)Command Rate: 2TDDR2 SDRAM Voltage: 2.1CPU Core Voltage: AutoFSB Termination V: 1.50 VMCH Chipset V: 1.65VICH Chipset V: 1.20VAll other settings are motherboard defaults.Maximum DDR2 recommended VDIMM: 2.1 Volts--------------------------------------Look at your modules and use the ones with the closest serial numbers if you mixed them up. Corsair say's if you exceed 2.1 Vdimm voltage you warranty is gone, but some mobo's don't supply enough voltage to the slots when they are filled up. They call it a DIMM loading issue. A slight increase, like 2.2-2.3 may fix it but it's chancy warranty wise!I think this is your board, going by memory here, if not it's something to start with. Should be close.Good Luck

>I never knew...that ASUS MB (and other MBs) has a limit of 2>Gigs without drastically making the whole machine a dog.>>MannyOh yes, running with full mem decks can slow down some systems. That was true a lot in the past and I guess (but don't know for sure with todays bleeding edge motherboards) that it is still true today.The suggestion about command rate is a good one, I would experiment with 1T and 2T and see what settings you can get stable and fast with your setup. Perhaps at 2T you can bump up the mem speed safely.RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

Guys...what is command rate.. 1T and 2T?I know how to adjust everything else... But I don't see that 1T and 2T anywhere in the BIOS.Manny

> ...... some mobo's don't>supply enough voltage to the slots when they are filled up.>They call it a DIMM loading issue.So for the new system I hope to build in about six month's time, would it be more likely to run properly if I got 4GB as 2x2GB sticks and thereby only fill up two DIMM slots, rather than 4GB as 4x1GB sticks (two 2GB kits)? Or is the "load" pretty much the same either way?The first option was a bit more expensive last time I looked, and I was really thinking of starting with 2GB and adding a second 2GB kit later on when needed. But if avoiding the "DIMM loading issue" really gives me more O/C potential, it might be worth starting with the 4GB kit.

Sorry Manny, I just saw that the P5W_DH doesn't allow command rate changes but it's actually set to 2T anyway.Jim Karn

Buck, I tried plugging each from the pair into the orange/black slot and the second pair of sticks to the second set of orange/black slots. But this time, it wouldn't even post. Noteven if I increase the voltage on the DIMMS. So I had to put it back to the matching pairs. Meaning...The oragne slots to 1 set of sticks and the black slots to the second set/pair of sticks.Ofcourse it runs when I slow the memory frequency down a lot. Aquamark benchmarks went down from 173FPS to 160FPS. FSX, I can't make out the FPS drop that much. Not sure..IF I should keep the 4Gig or return it.BTW..how about if I have a pair of 2Gigs i.e 2 X 2Gigs utilizing two slots? Would I have to then throttle down the frequency? I have no intention of going that route. Way too expensive now. But I am curious.Manny