Dell Optiplex 755 DT questions


Aug 9, 2017
Hey all,

I have a few questions about my trusty "Optiplex Prime", which I use mainly for budget-gaming. My goal is to max out this computer's potential and let it last until I can't stand it anymore, at which point I'll build my own computer that isn't from a surplus sale.

It's got 8 gigs of DDR2 800 MHz ram already, that's good there, and I've installed an Nvidia GeForce GTX 750 Ti GPU, and I'm happy with that as well. The only remaining bottleneck that can be widened further (as far as I know, and besides the obvious and inevitable SSD upgrade) is the CPU, so that's my focus.

I have an E6550 (Core 2 Duo, 2.33 GHz) installed currently, and I've been looking at either buying the Q6700 (Core 2 Quad, 2.66 GHz) or the Q9650 (Core 2 Quad, 3.0 GHz). According to the original documentation, Q6700 is the best that'll work, but multiple people have verified that the Q9650 will work on this model computer as well. My questions is, with my current graphics card installed, will power management be an issue if I go for the better Q9650?

If the stock PSU will be too weak to power it (pretty sure it's a 280W), my next thought would be to upgrade the PSU. I already know that the PSU is custom-made for the case and is shaped like an L to accommodate the disk drive. Would it be possible to simply remove the disk drive and use a better, not-L-shaped PSU, or is it more complicated than that? I've looked all over the place but it seems no one has asked this specific question before (that I can find anyway). Don't think I've ever even used the disk drive, so I wouldn't mind it being gone.

Also, what can you teach me about BIOS? I've got A13 currently, the internet says A20 is required for the Q9650, and Dell has up to A22 released. What are the pros and cons of updating the BIOS? The consensus I found is to not bother unless you absolutely have to; problem is, I dunno if I have to or not.

Thank you for reading, and thanks in advance for your help! Any other advice you can offer would be appreciated!

Nine Layer Nige

Apr 7, 2014
Being a luddite in Jurassic Park has its attractions.
I have done many OptiPlex 755 to A22 with no problem with a DOS bootable stick. At least if it all goes bad, you have not lost anything of value. The watts difference is 30w according to CPUBoss
The PSU is designed for that model so swapping out would be a challenge.
Unless you are doing this for kicks, scrap it and move into the 21st century.


II Pc User II

Aug 8, 2016
I have an optiplex 755 Dt and im running a thermaltake tr2 430watt. I just took out the 280watt psu and ran the new psu wires through the back, and now im running it like an xbox powerbrick lol.

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