If the molex cable is attached to a cable line that also has a connector type for a different device then the v/a for that device would be different to the v/a of the video card causing a different flow of v/a either way, resulting in a pause, lag, or freeze of one or the other.
Distributors of the same manufacturer model video card insert their distributor name into the header text of the information table of the video card so that it can be seen in DxDiag or aome other identifying software. Nvidia gets disgruntled when a distributor tweaks the video card to their own specifications rather than just Nvidia's requirements.
As to how Windows OS feels about the distributor name as compared to the manufacturrer is still a matter of conjecture but if the distributor uses their own name in the manfacturer type header information table then Windows will assume its a different manufacturer.You would also need todownload update drivers for each of the video cards instead of just one set from Nvidia therefore, also causing an issue of a sort.
XFX GTX 260 Black Edition, also a 260/216 version -
Specifications -
Core Mhz -576
Shader Mhz - 1242
Mem Hz -999
Memory - 896MB
Memory Bus - 448-bit
Stream - 192
(Verstion GT 260/216 - Stream 216)
Reference -
http://techgage.com/article/xfx_geforce_gtx_260_black_edition/
BFG Tech GeForce GTX 260 OCX Maxcore
Specifcations:
Core Clock: 655MHz
Shader Clock: 1,404MHz
Memory Clock: 2,250MHz
Memory: 896MB GDDR3
Warranty: Ten years (parts and labour)
Reference -
http://www.bit-tech.net/hardware/graphics/2008/09/25/bfg-tech-geforce-gtx-260-ocx-maxcore/2
The drivers for the XFX model are for all the 200 series as it makes it seem to appear, only the GT 210 is actually shown
http://products.xfxforce.com/en-us/Graphics_Cards/NVIDIA_GeForce_210/GM-210M-ZNF2XFX site
As for drivers for the BFG version, only Nvidia knows that one.
http://www.nvidia.com/object/IO_20021119_6780.html