Radeon 740G?

[duby229]

Hey guys I was looking into getting a new motherboard that could support the new Phenom CPU's But I'm on a pretty tight budget, and the only board I could find in my price range that is capable of running the new 125w CPU's has a graphics chip called the 740G....Heres a link to the board.....

http://www.newegg.com/product/produc...82E16813135076

So what is it? And what generation is this chip? Is it R400, R500, or R600?

Also this is kinda the wrong section, but how well does the Linux kernel support the SB700 south bridge?

[bridgman]

The 740G is an enhanced 690G. It doesn't map exactly onto 4xx/5xx/6xx but the best approximation is probably still R6xx display controller, R5xx 2D engine, R4xx 3D engine.

The main differences between 740 and 780 are :

- 740 is DX9, 780 is DX10
- 780 has UVD, although none of the Linux drivers support UVD today
- 740 has no vertex shaders, 780 has unified shaders, but with a fast CPU the vertex shaders don't make that much difference
- 740 has the "classic" 2d engine, 780 does all the 2d work on the 3d engine

[duby229]

The 740G is an enhanced 690G. It doesn't map exactly onto 4xx/5xx/6xx but the best approximation is probably still R6xx display controller, R5xx 2D engine, R4xx 3D engine.

The main differences between 740 and 780 are :

- 740 is DX9, 780 is DX10
- 780 has UVD, although none of the Linux drivers support UVD today
- 740 has no vertex shaders, 780 has unified shaders, but with a fast CPU the vertex shaders don't make that much difference
- 740 has the "classic" 2d engine, 780 does all the 2d work on the 3d engine

This might seem like an odd question, but right now I'm using a nvidia 6100 graphics to drive my primary monitor, and an nvidia 7600gt to drive the TV. It works great. the 6100 is fast enough for any desktop need, and the 7600 is fast enough to play most games and videos at either 1680x1050 or 1280x800... So my question is....

Will this card play nicely with nvidias blob driving the 7600gt? If so, how does the 740g compare to the 6100 on desktop performance?

[bridgman]

Using X with multiple GPUs is still in the "yeah, well, it should work but..." category. The RandR protocol doesn't seem to properly support multiple GPUs (although RandR 1.3 should) so quick answer is "I don't know".

re: performance against 6100, the 61xx parts seem to have 1/2 the pixel shader throughput but they do have HW vertax shaders. Seems like it's going to depend on your CPU -- if you have a decently fast CPU then the 690/740 might be up to 2x as fast, but if you have a sufficiently slow CPU then the NV part could match or maybe even beat the 690/740.

[duby229]

Using X with multiple GPUs is still in the "yeah, well, it should work but..." category. The RandR protocol doesn't seem to properly support multiple GPUs (although RandR 1.3 should) so quick answer is "I don't know".

re: performance against 6100, the 61xx parts seem to have 1/2 the pixel shader throughput but they do have HW vertax shaders. Seems like it's going to depend on your CPU -- if you have a decently fast CPU then the 690/740 might be up to 2x as fast, but if you have a sufficiently slow CPU then the NV part could match or maybe even beat the 690/740.

Excellent. So at this point it is a "try and see" kinda thing. And if all else fails then I just have to wait for RandR 1.3. OK makes sense.

I'll be getting a new Phenom and this board when I get the Federal Stimulus check in the mail. That should take care of vertex shaders.

What is the benefit of doing vertex shaders in software? Clearly less hardware, but is that all? Are modern CPU's fast enough that vertex shaders arent important anymore?

[bridgman]

Before we all moved to unified shaders, removing vertex shaders saved die size and cost, and since most IGP sales were with new CPUs there wasn't much performance loss. It was just a major pain for driver developers.

CPUs do vertex shading better than pixel shading, so as long as you're not looking at a high end part you can do vertex shading in SW without much of a performance hit.

The big problem is that badk in the dark ages integrated graphics used to be "free" since the northbridge parts were pin-bound, ie the die size was determined by the number of pins not the amount of logic on the chip. Adding a simple GPU did not raise the die size so it could be considered "free".

These days GPUs on a Northbridge are no longer free due to advances is fab process technology but they are still incredibly cost sensitive.

[Kano]

You can not mix fglrx with nvidia, thats impossible as nvidia replaces the libs.

[duby229]

You can not mix fglrx with nvidia, thats impossible as nvidia replaces the libs.

What about the nvidia blob and open source radeon? No prolly not due to nvidia overwriting the opengl libraries?

How about nouveau and radeon? Does nouveau support 3d acceleration on the 7600gt? Also does the radon support 3d acceleration on the 740g?

[bridgman]

Radeon supports 3D on 690, so if it doesn't work with 740 then it's probably just a few IDs away from working. The work to add radeonhd plumbing to use the same 3D code (mesa and drm) is almost finished, so radeonhd should be fine for 740 as well.

I don't think we have a 740 in the pool of HW we use for open source dev and test but will try to add one.

IIRC there are some IGP-specific 3D issues which would also affect 740, related to SW emulation of vertex shaders, but as more devs come up to speed on the ati mesa drivers we should be able to pick those issues off fairly quickly.

EDIT -- just to be clear, I'm talking about supporting 740 as the only running graphics device, not running at the same time as a proprietary driver from any vendor.

[VaHyper]

Anyone got some information about how 740G works in Linux today?

Thinking about getting one and I heard 690G works very good now and since the graphics card is almost the same this should work just as good I assume.

I just want descent 2D performance and be able to play videos ok, not interested 3D stuff...

I assume the SB700 southbridge is a little better than SB600 for harddrive performance too?
The 740G chipset seams perfect for me that just want a low power computer with fast harddrive and network performace (getting a intel pci-express NIC).