3 Replies Latest reply on Dec 6, 2010 6:24 PM by mechbob

    Upgrading to 1066 or 1333MHz CPU with PC-6400 RAM




      I have an HP a6600f, and am confused about the processor upgrades HP lists as recommended.


      I have the Foxconn NAPA (GL8E) Motherboard

      4GB of PC-6400 RAM (DDR2-800)

      Intel E4700 Core 2 Duo CPU

      nVidia GTX 460 video card

      Creative X-Fi Titanium sound card


      I'm confused because HP says I can put a CPU in my PC that runs at either a 1066 or 1333MHz FSB.  However, the fastest RAM it will take is DDR2-800.  I originally had the E2200 CPU installed, and upgraded to the E4700 because it was the fastest processor listed that matched my memory specs.


      Now I'm being told I can put a faster FSB CPU into my PC, and that my RAM will underclock to match the CPU, but that isn't the 1:1 ratio I am used to.  That would be 2:1, with the processor running at twice the speed of the RAM.


      The E4700 helped a LOT with my PC games, like Dawn of War II.  I gained the ability to turn on Shadows on High when they had to be off with the E2200.  All the setting were able to be raised to the max, except Terrain Detail.


      Since I was getting 5 FPS as a minimum reading with the E2200, and now it's up over 20 FPS as the lowest reading, I have proven that the CPU was the bottleneck.  Still, I would like to be able to turn everything up on MAX.  Still can't quite do this with the E4700.  This tells me that an even faster CPU is needed to crank everything up to the MAX.


      Question: How does it benefit me to put a 1066 or 1333MHz FSB CPU in my machine with RAM that tops out at 800MHz.  Wouldn't the RAM then become a bottleneck?  Would I acutally get MORE performance from mis-matching the CPU FSB and the RAM speed?  I'm told the RAM will underclock...


      I'm used to matching everything 1:1.  The only time I didn't do that was when the roles were reversed.  Back when the FSB of a CPU was 66MHz, I could put PC-100 RAM in and it would clock down to the CPU FSB.  THAT makes sense to me.  However, the reverse does not.  If the RAM can't keep up with the CPU, it seems that would be a problem.


      Could someone please explain this to me?  Please put things in simple terms for me.  Yes, I was certified years ago as an A+ Certified PC Tech, but it's been YEARS since I have built a system from the ground up, and if I were to do that today, I would still make sure there was a 1:1 ratio with the CPU and RAM.  Why would I put a faster CPU in a system with slower RAM?


      Thanks in advance for your help.  I DID search the forums for an answer, but couldn't come up with one, hence this new post.