bit-tech published a review of XFX's GeForce 8600 GT 620M XXX Edition

Despite the lack of HDCP support in the current version, XFX's GeForce 8600 GT XXX Edition is probably one of the best bang for buck mid-range DirectX 10 graphics cards out there. From as little as £90 including VAT, the card delivers performance that is not too far off Nvidia's GeForce 8600 GTS and, with a bit of overclocking, you can achieve practically the same performance as the 8600 GTS.

The cheapest GeForce 8600 GTS out there today will cost you around £110 (inc. VAT), which is another £20 more than the XFX GeForce 8600 GT 620M
XXX Edition. First, you have to first ask yourself whether the extra £20 that XFX's card costs over a standard clocked 8600 GT is worth spending, and then you have to ask yourself if it's worth spending another £20 to get an 8600 GTS. Stretching to £90 would be worthwhile, in my opinion, but stretching to £110 will not make as much of a difference.

XFX GeForce 8600 GT 620M XXX Edition Review