I have been running Q9550 at 430x8.5=3655Mhz + 2x2GB OCZ2P10664GK ram at 400Mhz 5-5-5-18-54-2T for a few years stable.
However with the same settings, now that I added another 2x2GB of the same ram for total of 4x2GB, I get instant black-screens (shutdowns without bluescreens). I ran memtest86 and got about 8 failures in 1hr at 430x8.5, and about 2 failures in 1hr at 400x8.5. However, the black-screens still happen regularily in Games at lower clock speed 400x8.5, regularily means my system turns black within 30min in starcraft2. But so far no black-screens when under normal win7 environment running photoshops.
anyone with experiences on 4 sticks ram upgrade? some directions on improving stability in games would be appreciated. ( I'm sure the sc2 bnet ladder players would greatly appreciate it too)
You can attempt to loosen your timings a cycle or two, that may put the ram at a point of harmony. Here's what's likely going on, Ram tends not to like other ram, even ram from the same manufacturer with the same model number and specs. Ram manufacturers, during the binning process (I believe that's when it's done - it may be a separate process) find ram that plays well with one another and then sell them as a matched kit. Which is part of the reason as kits have more modules they get more expensive per gigabyte - even though they appear to be identical modules as the smaller kits. One of the many strange things I've found about ram over the years.
Just as a side note: this is becoming far less common than in the past but it still does happen.
There may be other issues but that's what I'm thinking it is.
6-6-6-18-54 still causes shutdowns. 7-7-7-20-54 simply won't even boot. and I only run it on 400x2D ....
the default auto is 5-7-7-20-54 from BIOS, I know it will still causes shutdowns in game, but at least now I can post replies on internet.