06-08-2016 06:23 AM - edited 06-08-2016 06:23 AM
Have you replaced the stock Lenovo 280W PSU? I thought the GTX960 required additional PCIe power from the PSU, and there's no such cable on the Lenovo PSU's.
Without addressing the PSU problem, your best bet is to go with an EVGA GTX 750ti SC card. This is low-power card and works perfectly with the 280W PSU in assorted Lenovo tower machines.
06-09-2016 03:31 AM - edited 06-09-2016 03:33 AM
Don't know what to say.
Very common for older motherboards with older BIOS to just not be able to support latest GPU's which are often too fast for the older machine hardware. PSU capability is only one part of the equation. It may simply be that the GPU on the GTX960 is just too strong for the M90, as the BIOS beep code is trying to tell you.
You may have to stick with a somewhat older/slower graphics card if you're wanting to keep the M90 machine, which itself is quite old. The GTX750ti cards are very good, and don't need any additional power. Not a high-end super gaming card, but 86GB/s bandwidth is very very good and the price is right.
Investing in a newer machine (e.g. M800 or M900) and using the PSU you just got in that new machine so that you can almost certainly then use the GTX960 in it, well that's of course up to you.