I heard many saying ONLY Linux can able to detect more than 4 GPU's & Windows won't detect more than 4 GPU's.
ONLY Linux can able to use up to 8 GPU's or more.
Windows won't detect more than 4 GPU's is completely false & wrong.
Windows detects more than 4 cards at least in my rig, i have 7 cards so far & windows detects all the 7 cards.
Its the MINERS which WON'T mine more than 4 GPU's in Windows.
I am not sure, it was done intentionally or unintentionally.
Because normally Linux needs more work than Windows due to its open source & geeky & intellectual type.
With Linux you can do wonders with out paying even a single penny or bitcent, completely free.
But you have TO KNOW Linux programming & its structure .....
You can't just download, install & work in a software.
Linux needs more from you, make you learn more.
Since, Bitcoin developement MUST be free from all, it adopted open source & to make Bitcoin work early developers used the open source Linux for bitcoin client & also miners.
Gavin & his early developers created Bitcoin client both in Linux & Windows.
They simply know & wanted Bitcoin to spread as fast as it can.
But, the same didn't happen in miners.
I have so far never seen Gavin replying or developing mining program. His interest is to make Bitcoin the international currency both for online trading (internet) & offline trading (local).
Miners are mostly created in Linux then as many Windows users too wanted to mine, Windows binaries released.
In my opinion, here the CONTROLLING came. Forcing/blocking intentionally or unintentionally windows not to mine more than 4 GPU's.
In windows everything can be done even as novice. This seems not liked by some, so they put restriction.
The above picture clearly shows Windows with 7 GPU's.
4 are MSI R6970 graphics cards
2 are ASUS EAH5870 graphics cards
1 is Sapphire HD 5870 graphic card.
All are connected using extender cables from cablesaurus. NO crossfire cable used. Mother Board is MSI Big Bang Marshal.
Still one pcie slot is free, to which i can add another graphics card & can have 8 GPU's in Windows.
The OS is Windows 7 Ultimate, 64 bit.
I try to mine with 2 softwares & its variants.
Phoenix & Poclbm.
I tried GUIminer, PR up to 1.62, directly used phoenix & poclbm in command prompt also.
I disabled 3 cards & i run the above miners & it can able to mine with out any problem.
The minute i enable 5th card in device manager, miner gives error & exits.
Then whatever i do, miner both phoenix & poclbm just gives error when ever started, that it encountered a problem, search online for solution or close......
The moment i disable 5th card, i can able to mine.
All these done with out rebooting system.
I request mining program developers to review their code on windows.
I am not good in programming, so i can't do much myself.
Please rewrite your mining programming so Windows too mine more than 4 GPU's.
If not then the base for which Bitcoin is fighting won't be their. NO CONTROL BY ANYONE is the motto on which Bitcoin travels. That is killed by locking mining program not to mine more than 4 GPU's in Windows OS.
Its not order, but a humble request from a Windows user.