on ac power.but not this is the problem,the thing is y dont understand why the dedicated ati 6650m is on 32bits bus on the system and not on 128bits bus as it is listed on notebookcheck.if this is true the performance is realy bad for a dedicated card;or it may be a catalyst issue that it doesnt recognize corectly the card or it needs an update bios for gpu by amd.the same thing is also on asus k53ta same configuration...

http://www.notebookcheck.net/AMD-Radeon-HD-6650M.43962.0.html  -as shown on 128bits bus

http://www.notebookcheck.net/AMD-Radeon-HD-6720G2.57274.0.html    -is doesnt show 6720g2 in crossfire mode,but only 6520g

http://www.notebookcheck.net/Review-Asus-K53TA-SX026V-Fusion-Notebook.62849.0.html ---the ati 6650m is on 32bits,as shown on my lenovo z575 gpuz,aida64 and everest

I'm not much on graphics, but are you confusing system bus with dedicated memory bus width?

AFAICS, system bus refers to PCI or PCIe bus, and the memory width (128 bits for example) is the width of the connection between the graphics chip and its dedicated memory.  The graphics logic needs both connections.

Just asking,

Z.

Hello,

In the end, does the z575 have crossfire or not. i have been reading a lot and some people say that the video cards function only one at a time. So when more chalenging task are required the discrete card is used and when not the integrated one.

Someone in another thread said that :

"

"

This is the forum thread i was talking about :

http://forums.lenovo.com/t5/IdeaPad-Y-U-V-and-Z-series/Z575-freezing/td-p/645957/page/2

I would really like this laptop to have crossfire and the both video cards to be used at the same time.

So doest it support crossfire or not?

Can someone please tell me.

Thank you.

Z575 does support Crossfire (or Dual Graphics), but from what I could understand by default (without installing Catalyst Application Profiles) it only works for DX10 and DX11 applications (as the official website claims):

Q5: Why doesn’t my DirectX® 9 game look better on AMD Radeon™ Dual Graphics?

A5: AMD Radeon™ Dual Graphics was designed only for the latest DirectX® levels to allow AMD to focus resources on providing an optimal user experience on the latest graphics technologies. AMD encourages users to take advantage of these and numerous other innovations that have come to market recently by upgrading system hardware.

AMD Radeon™ HD 6000 Series graphics, found in both AMD A-Series APUs and discrete video cards, are designed to deliver the best possible DirectX® 11 experience. As such, the dual graphics performance increase is applicable to select DirectX® 11 & DirectX® 10 enabled applications. For DirectX® 9 applications, the combined performance will be disabled and the fastest graphics engine will perform those tasks; however, users will still experience the speed and performance of AMD Radeon™ graphics.

In order to monitor the graphics card utilization you can use AMD System Monitor. With this tool I could confirm that, for instance, Unigine Heaven Benchmark uses Dual Graphics in DX11 and DX10 modes and only uses a single card in DX9 mode with Lenovo drivers, as it should. I could also confirm that Assassin's Creed: Revelations (DX9) only uses one card with Lenovo drivers, gives black screen after installing CAP on Lenovo drivers, however it actually uses Dual Graphics with AMD official drivers w/ CAP installed.

So in order for DX9 games to use Dual Graphics and also in order to get some speedups and fix glitches when using Dual Graphics one has to install Catalyst Application Profiles (which don't work properly with Lenovo drivers). Of course, there has to be a pre-made profile for a game, unless you use Catalyst 12.1 which made it possible to force a preinstalled Crossfire profile to a game which doesn't have one giving users a chance that it may work in Dual Graphics mode if proper profile is applied to it.

AMD official drivers can't switch off Lenovo's 6650M properly, so the system hangs when using discrete graphics unless you disable ULPS which keeps 6650M always on. With Lenovo drivers the card switches off properly, but CAP don't work properly with these drivers (so no Dual Graphics in DX9).

That's why I wish either Lenovo made their drivers compatible with CAP or for someone to learn how to mod official drivers to disable/enable 6650M properly.