Most helpful critical review
Works, but don't trust the VGA out port if using Linux xorg drivers on old LCD monitors
on September 2, 2013
I ordered 2 of these, used from different suppliers. I'm not certain it is the card's fault, but for some reason, on one of the cards, the VGA-out port burned out 3 older LCD monitors, before I figured out what was going on. This probably is not be the fault of the manufacturer, and is likely the fault of the experimental xorg drivers that I was using while running LINUX, and trying to use 6 monitors at once. I suggest if you are using Linux that you only use the nouveau drivers or the NVIDIA proprietary drivers. The older 4:3 Dell 17" monitors circa ~2005 I guess could not handle what was being sent to it, and they became dim before burning out. I'm guessing the inverter boards got fried, but I don't know. After losing 3 monitors, I wasn't in the mood to test it out that port with other monitors. The HDMI-out and DVI-D ports on each card seem to work fine. The HDMI-out ports work with HDMI to VGA adapters.
THE DVI REQUIRES A DVI-D (single-link) CABLE, AND NOT ANY OTHER KIND OF DVI CABLE OR ADAPTER WILL WORK! (see [...] for more info)
This card is almost equivalent to an ATI 7750 for gaming, and it has about the same wattage as a 7750, runs off power provided by the PCI-e bus, and it does not require any supplemental power from the power supply, which is nice. The fan is rather bulky, so the card takes up 2 slots, which not every GT 640 does, but these cards were not expensive, and they work fine.
This card is not as good as the ATI 7750 for virtual currency generation, but it is supposed to be maybe better for gaming. The GT 640 is supposed to work easily with OSX86, but I haven't quite got to that yet. I did not test it with Windows, as I don't use Windows.