Question System compatibility GPU upgrade


Nov 10, 2015
Hello everyone,

I'm currently looking into upgrading a friends GPU.
He wants to spent the least amount of money possible....
So i've proposed to let him borrow my old GPU.
Because he has a prebuilt system i've run into a couple of problems.

First off, the specs
Intel I7-3770
WD blue 500GB
10GB RAM (brand unknown)
GT640 (to be replaced with HD7950 or HD6950)
AcBel Polytech inc PSU model: PCA246 (460W) with the mention of "standard efficiency".

So my questions are
  1. Is an HD6950 (or HD7950) a significant upgrade to the GT640 in terms of real world use.
  2. Will the 460W power supply be enough? (According to some online PSU calculators i'd need 403W, but i'm not sure if the PSU actually delivers 460W)
  3. Should anyone find some info on the available connectors, the cards both need 2x8-pin if i remember correctly, it's currently borrowed to another friend.
If anyone could shed some light on this case, i'd be a little more at ease with installing this GPU (unless ofcourse I shouldn't)

Best regards


  1. Yes, both cards would be an improvement; considerably so. The HD 6950 about 150%, the HD 7950 about double that.
  2. Unfortunately, both of those cards would be unsafe with the 360W available at the +12v rail on the PCA246 (460W). They would work, but you are taking a chance of anything from low performance, shutdowns, to killing the PSU.
  3. I doubt that PSU has anything other than a single 6 pin for a graphics card anyway. And using adapters from any unused Molex connectors is never a good idea.
The RX 470 or GTX 1060 would run nicely on that PSU, and provide better performance than either of those HD-x950 cards. But he would have to spend some money. If that is out of the question, a better PSU may be the next best move.

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