CPU/Motherboard compatibility

[Starp]

I'm upgrading my computer to a modest gaming PC at the moment, all I need is a new CPU, so I've decided to go for the best my socket LGA775, 800MHz board can handle- the Intel Core 2 Duo E4700.
However, I've heard some motherboards can handle speeds greater than the front bus should be able to. Mine can handle 800MHz memory when it should only be able to run 400, so can anyone confirm this for me? It'd be nice to run at 1066MHz for that extra something.

 

[Squarewave]

the buss speed doesn't run at the same speed as the ram. There is a multiplier that increases the speed of the buss to match the ram the best it can.

Ram can also run at speeds lower then they are rated at.

For example a 200mhz buss that can run at 4x multiplier can run 800mhz ram at 800mhz, however you can use 1066 ram and it will run at 800 mhz if the cap for the motherboard is 800

My numbers are off as I havn't shopped for motherboards in a long time, but thats the jist of it

 

[Horticulture]

I'm upgrading my computer to a modest gaming PC at the moment, all I need is a new CPU, so I've decided to go for the best my socket LGA775, 800MHz board can handle- the Intel Core 2 Duo E4700.
However, I've heard some motherboards can handle speeds greater than the front bus should be able to. Mine can handle 800MHz memory when it should only be able to run 400, so can anyone confirm this for me? It'd be nice to run at 1066MHz for that extra something.

What model is the motherboard? If your motherboard supports DDR2-800, it most likely has a FSB speed of 400 mHz. Like Squarewave mentioned, this is due to the multiplier (DDR2 runs at a 2x multiplier, so a FSB of 400 mHz gives you DDR2 RAM running at 800 mHz (400x2). The 'CPU FSB' is actually different from the base FSB speed (confusing, isn't it?) because Intel's Core 2 line is 'quad-pumped', meaning it runs at a 4x multiplier. So continuing with the assumption that your motherboard has a base FSB of 400mHz, the CPU FSB will be 1600mHz(400mHz x 4).

 

[Starp]

Ha, I've been looking at the CPU bus rate, thanks guys.
I've just looked up the documentation, and it turns out the board can handle 800 or 1066MHz rates. Now considering I know about sockets, anything else I should know before I dive in?
Thanks again.

 

[Horticulture]

Ha, I've been looking at the CPU bus rate, thanks guys.
I've just looked up the documentation, and it turns out the board can handle 800 or 1066MHz rates. Now considering I know about sockets, anything else I should know before I dive in?
Thanks again.

See if you can find a compatibility list on the manufacturer's website. Some boards won't support certain processors even though they will support both their socket and bus speed. Mine, for instance, is a socket 775 with a CPU-FSB of up to 1333 mHz, but won't support 45nm Core 2 Quads, though it'll support dual-cores running at the same speed.

 

[Theo Samaritan]

Now considering I know about sockets, anything else I should know before I dive in?
Thanks again.

Yea, get a Core 2 Quad 6600. If your motherboard supports Core 2, it will most likely support that. Check the cpu compatibility sheet on the vendors website to see what it really can take - E4's are quite bad, to be fair. Q66's are no longer being produced so they should be cheap, but in theory you could take the newer Q7's to Q9's

 

[Starp]

Well I really appreciate all the help, but I'm having no luck finding any kind of compatibility chart for my E187242. I suppose I could go straight in and get a Core 2 Quad, but as this is basically the home computer equivalent of a brain transplant, and this isn't actually my computer (parents'), I'd better not risk it. I'll keep digging and see what I can salvage.

 

[Oopsie]

IS this your computer?
http://www.dell.com/content/products/productdetails.aspx/dimen_5150?c=us&cs=28&l=en&s=dfb

 

[Starp]

Not quite, it's the Dimension 5100, but as long as the board's the same, I doubt it'd matter.
Good deduction, by the way, not far off.

 

[Oopsie]

Ah well, almost on the mark . The 945G E chipset does support core 2 duo CPU's, but the main question here is will the BIOS? If it doesn't recognise it, it may not function properly. Unless you can get some definitive information from Dell about this, don't risk it. Especially if it's not your computer.

All I could find in a pinch was this;
http://support.dell.com/support/downloads/download.aspx?c=us&l=en&s=gen&releaseid=R129666&SystemID=DIMENSION%205100&servicetag=&os=WW1&osl=en&deviceid=308&devlib=0&typecnt=0&vercnt=3&catid=-1&impid=-1&formatcnt=1&libid=1&fileid=172847

A word of advice: Dont buy a Dell for yourself.

You could also try and download a programm called CPU-Z, which will hopefully reveal some more info on your motherboard.

 

[Horticulture]

Well I really appreciate all the help, but I'm having no luck finding any kind of compatibility chart for my E187242. I suppose I could go straight in and get a Core 2 Quad, but as this is basically the home computer equivalent of a brain transplant, and this isn't actually my computer (parents'), I'd better not risk it. I'll keep digging and see what I can salvage.

Plugging in a few variations of "945g" here [http://processormatch.intel.com/CompDB/] yielded the c2d e6X00 series, e4X00 series, and a few Pentiums (2X00) and Celerons. None of the quads (including the Q6600 recommended above) appear to be compatible.

 

[Starp]

Alright, thanks a lot guys. Intel Core 2 Duo E6700 it is. If you ever hear from me again, you'll know the operation was a success.