Memory Speed and FSB

[aznxkigga]

Ok, so I read in other posts that your memory speed should match up with your FSB to get maximum performance. I have a Dell P4 2.80Ghz 533Mhz FSB. Does this mean that I should run PC2100/266Mhz memory? This doesn't make sense since my motherboard only supports PC2700/333Mhz or PC3200/400Mhz. I just bought 1GB Kingston HyperX PC3200/400Mhz and the frequency of my memory according to CPU-Z is 166Mhz, making the FSBRAM ratio 4:5. Did I just waste my money by getting faster memory (old memory was 512MB PC2700/333Mhz)? Please explain!

 

[Matthias99]

Intel likes to multiply their bus speeds by 4, rather than by 2 (there's some technical truth behind this, but mostly it makes the numbers sound bigger, and everyone knows BIGGER NUMBER ARE FASTER!!!!!!).

A "533Mhz" Intel FSB uses 133Mhz (DDR266) RAM; their "800Mhz" FSB uses 200Mhz (DDR400) RAM.

Edit: uh, 533 / 4 = 133. Duh.

 

[imported_Computer MAn]

The PC3200 will just downclock to 166mhz because you can run the memory no higher than the FSB ususally.. Your new memory right now is running the same speed your old memory was at because Intel quad pumps their CPU's so a 533FSB is really 166mhz. Your PC2700 at 166mhz but is applied twice per cpu clock making it 333mhz. PC3200 that you bought runs normally at 200mhz applied twice per clock so effectively 400mhz. CPUZ reports the base speed before it is doubled meaning the memory is running at 166 base doubled to 333.

 

[aznxkigga]

So basically, running PC2700 and PC3200 memory on my computer is the same? What's the point of being compatible with 400Mhz memory if my motherboard only supports up to 333Mhz?

 

[beatle]

There's no point unless you overclock (not possible on a Dell) so you wasted your money. It'll be nice if you upgrade, however, but it's not necessary in your current system.

 

[bfonnes]

Originally posted by: beatle
There's no point unless you overclock (not possible on a Dell) so you wasted your money. It'll be nice if you upgrade, however, but it's not necessary in your current system.

can't you just find out what board you have, and reflash it with that board's generic BIOS?

BFonnes