First off, this is my first post here and I'd like to thank everyone who blazed a trail and posted helpful info on upgrading Dell E510 and E520 computers. I found numerous helpful threads that helped me upgrade my aging E510 and have made me look seriously at buying and upgrading an E520 as a low cost alternative to a new machine. In that spirit, I want to record all of the useful info in a single place so anyone looking to do this in the future doesn't have to pour over ten different threads like I did to try and piece together the info to upgrade their E510. So here's my experience...

My current machine is an E510. It originally came equipped with a Prescott P4 630 @ 3.0 GHz and an OHJ054 motherboard. As suggested on these forums I was able to upgrade to a Presler P4 D 945 @ 3.4 GHz with zero problems after first upgrading my machine to BIOS revision A07.

Here are the steps you should follow if you wish to upgrade your E510.

1. Download CPU-Z. Links die, so Google it, it's handy and free.

2. Find out which model motherboard/mainboard you have. If you open up your PC it will have a model number printed on the mainboard, pay no mind to it, and instead use CPU-Z to get your info. The number printed on my board was useless for finding info; CPU-Z tells me that I have an OHJ054 motherboard which is what you want. Fear not, if that's no your model number you can still upgrade your CPU, you'll just get a clearable error message when your PC starts up. Also, your motherboards chipset called Intel 945G.

3. Press F2 during startup or use CPU-Z to find out which version of BIOS you have. You want/need A07, get it from Dell's support downloads website.

3. Buy a processor. Socket LGA 775, Intel Pentium 4 or Pentium D. Prescott, Cedar Mill, Smithfield or Presler processors from the 6xx, 8xx, and 9xx series model numbers will work. Prescott and Cedar Mill cores have nearly identical performance, but Cedar Mill cores (identified by a 6x1 model number instead of a 6x0 model number found on Prescott cores) have a smaller architecture 65nm for Cedar Mill vs. 90 for the Prescott cores. Pentium D processors are dual core and basically use two cores printed on a single chip which run in tandem. These processors have 8xx and 9xx model numbers, 8xx models use 90nm architecture and 9xx models use 65nm architecture.

The Intel Pentiun D 945 @ 3.4 GHz is reported to be the fastest processor you can handle with a factory motherboard, supposedly going with the 950 (basically identical to the 945 won't work, which is likely due to the fact that the 950 has a 120W power requirement instead of a 95W like the 945 and below).

Finally, consult Wikipedia’s “List of Pentium Processors” for exact info. What I found there seems to be generally reliable and almost all of it agrees with what I’ve found posted on these forums.

4. Install said processor and prepare for disappointment. Yes, its faster. And yes, its still slow. Bummer. Using Performance Test my factory system posted a 440 composite score, with the upgraded processor I scored a 575 composite. Not bad really for a single $40  upgrade since its a 30% increase in performance, but I don't really notice that much of a difference in speed while using my PC daily. For reference, a medium performance home PC with one of today's dual core processors should score in the 2000-3000 range on this test, so don't expect brand new PC performance with this upgrade.

All in all it was certainly worth the $40 ($30 for the processor on eBay and $10 for some new thermal compound) as the machine does seem to handle multiple simultaneous taks better (thanks dual core!), but I think my money would have been better spent picking up an E520 and upgrading it instead.