Nvidia GT 640 1GB DDR 5 VS R7 250 DDR 3 2GB

Solution
Radeon R7 250 is better because the clockspeed is 1000mhz instead of 900mhz by the Geforce GT640. And the memory speed is 1150mhz instead of 891mhz and the memory performance of the Radeon R7 250 is 26% better in performance but the recomended PSU is 400 watt for the radeon and 350Watt for the Geforce.

ikaz

Distinguished
It hard to find bench marks on such low end cards however if your talking about the 1GDDR5 version of 640 it should be much better than the 2 GDDR3 R7 250 because GDDR5 is much faster and has better bandwidth than GDDR3. In low-ends like that you will "choke" on the gpu speed before hitting a memory size limit.
 

Dutchpixel

Commendable
Feb 26, 2016
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Radeon R7 250 is better because the clockspeed is 1000mhz instead of 900mhz by the Geforce GT640. And the memory speed is 1150mhz instead of 891mhz and the memory performance of the Radeon R7 250 is 26% better in performance but the recomended PSU is 400 watt for the radeon and 350Watt for the Geforce.
 
Solution

Dutchpixel

Commendable
Feb 26, 2016
110
0
1,710

If you want to spend a little bit more then go for the gtx 750 ti. It costs $134 and is much better compared to price and performance.