However, as I was in the process of dismantling a system with an Intel Core Quad Q6600 CPU using the same Socket 775 I wondered about upgrading the DELL with it.
Even though DELL claimed that this processor was not supported in the E520 others had tried successfully. So, I upgraded to the latest 2.4 version BIOS and dropped it into the E520 and it booted.To make the most of this better CPU, I was able to load Windows Vista Home on to the system. However this required upgrading the memory to 2Gb. I only had a couple of PC6400 DIMMs which again DELL said it didn't support. However, in they went and worked at the faster speed. Swapping the 80Gb drive for a 200Gb was the next step, followed by adding an old Radeon HD4550 graphics card.
Now the performance test using PCmark05. The original system struggled to 2,217 yet the same test gave 7,667 on the upgraded system. Quite a difference and well worth the double asking price. A really successful mid-life upgrade to a quality system.