Hello i want to find out the max amount of ram my pc can use. I have a dell which is um....yeah. Dell themselves say i can do only up to 1gb with a speed of pc2100. But i also tried the crucial online memory scanner and i get results that are very very different. For one it tells me i have a Dimension 4500S when i have a 4500. It also tells me i can do up to 2gb of ram with a speed of 2700, or 3200. My motherboard is an intel D845EPT2 and my chipset is i think a I845. Please help me i really gotta upgrade it.

Looks like Crucial is correct: ftp://download.intel.com/support/motherboards/desktop/d845ept2/PRODUCTBRIEF.PDF

If your Dimension is a 4500, that's the info you should be looking for, not a 4500S. Online scanners are not 100% reliable. If you check the specs for the 4500, both Dell & Crucial agree that 1GB (2 x 512MB) is the max. http://support.dell.com/support/edo... http://www.crucial.com/store/listpa... As for which RAM to get (PC2100, PC2700 or PC3200), it really doesn't matter because they are all backwards compatible. But be aware that you're not gonna gain any performance by running PC3200 because your CPU runs at either 100MHz or 133MHz bus speed. The "effective" speeds are 400MHz or 533MHz due to Intel's "quad-pump" technology, but you have to work with "real" bus speeds, not effective. With a 400FSB CPU (@ 100MHz) you should be running either PC1600 (@ 100MHz) or PC2100 (@ 100MHz, possibly 133MHz). With a 533FSB CPU (@ 133MHz) you should be running either PC2100 (@ 133MHz) or PC2700 (@ 133MHz, possibly 166MHz). PC3200 can be used, but it should be underclocked to PC2100/2700 speed, depending on which CPU you have.

I know my FSB is 100mhz and that the cpu has a 20x multiplier. Both are Locked

What if i get a 2.8ghz pentium 4, would that help me with the ram or will it just give me a speed increase in the ghz.

I answered your question & provided links...maybe you don't understand? Since you have a 100MHz FSB CPU, it would be pointless to run the RAM faster than 133MHz. There would be no performance gain, in fact, the system may perform slower. It doesn't matter which RAM you get (PC2100, PC2700 or PC3200) as long as you run it at 133MHz (max).