cancel
Showing results for 
Search instead for 
Did you mean: 

Archives Discussions

grizlyk
Adept II

AMD 785G (HD4200) chip and ATI stream (OpenCL)

supported or not?

Hello.

From official AMD 785G Chipset Overview page: ATI Stream | A set of advanced hardware and software technologies that enable AMD graphics processors (GPU), working in concert with the system’s central processor (CPU), to accelerate many applications beyond just graphics.

I have the chip onboard and i have another HD external card, they can both work simultaneously. Can i use internal onboard card for some OpenCL computing?

This is not very clear the mist about the question - nobody knows?

 

0 Likes
11 Replies
nou
Exemplar

no that chipset is based on old RV620. so it is not supported. you need at least RV7xx based GPU. ATI Stream on that page mean older CAL/Brook capabilities.

http://developer.amd.com/gpu/AMDAPPSDK/pages/DriverCompatibility.aspx

0 Likes

Also, even if it were supported, it's only rated at 40 GFlops, which is less than 5% of performance you could get out of any middling ATI card nowadays. You'd have a hard time designing a program that runs faster on your HD4200 chip than on the CPU.

0 Likes

Originally posted by: nou no that chipset is based on old RV620. so it is not supported. you need at least RV7xx based GPU. ATI Stream on that page mean older CAL/Brook capabilities.

  http://developer.amd.com/gpu/AMDAPPSDK/pages/DriverCompatibility.aspx

Exactly, first link say 'yes', but the last say 'no'. That results in confusing people over inet. In fact, the question is: the HD4200 has no hardware to execute OpenCL or this is OpenCL software issue to does not support HD4200?



Originally posted by: eugenek Also, even if it were supported, it's only rated at 40 GFlops, which is less than 5% of performance you could get out of any middling ATI card nowadays. You'd have a hard time designing a program that runs faster on your HD4200 chip than on the CPU.
All things are relative. The GPU+CPU perfomance in comaprison with empty CPU performance is subject to consider. While CPU works with other jobs, GPU could process own task in true parallel mode.

For me personaly it does not matter - i can switch into onboard GPU to get 2D view and use external card(s) to OpenCL, but it is just curious.

 

0 Likes

grizlyk,
I don't see anything in the first link that states OpenCL support and the device is not listed as compatible in the DriverCompatibility link.
0 Likes

Originally posted by: MicahVillmow grizlyk, I don't see anything in the first link that states OpenCL support
Why, excuse me, the repeated quote 
ATI Stream | A set of advanced hardware and software technologies that enable AMD graphics processors (GPU), working in concert with the system’s central processor (CPU), to accelerate many applications beyond just graphics.
As i know "ATI Stream" is the same as "OpenCL" or what? If they are different, what SDK can i use for "ATI Stream" for HD4200?

Originally posted by: MicahVillmowand the device is not listed as compatible in the DriverCompatibility link.
Do you mean the last link? The first one is chip description and does not refer to any "DriverCompatibility link".

0 Likes

grizlyk,
OpenCL is a subset of ATI Stream. ATI Stream also includes CAL and Brook+ which that device supports, but does not support OpenCL. Basically that chipset can use SDK 1.4 here:
http://developer.amd.com/archi...eta/Pages/default.aspx
0 Likes

Originally posted by: MicahVillmow grizlyk, OpenCL is a subset of ATI Stream. ATI Stream also includes CAL and Brook+ which that device supports, but does not support OpenCL. Basically that chipset can use SDK 1.4 here: http://developer.amd.com/archi...eta/Pages/default.aspx
Well, thanks, i will take a look.

And, by the way, if the short answer exist and has a sence: why i can not do:

// create a compute context with GPU device
context = clCreateContextFromType(0, CL_DEVICE_TYPE_GPU, NULL, NULL, NULL);
with HD4200 - no GPU hardware or no OpenCL software?

 

0 Likes

The HD4200 is based on the RV620, which does not support Compute Shader. OpenCL uses compute shader to execute kernels. So the hardware support on that device does not support OpenCL, so OpenCL does not recognize it.

To use the Stream SDK you need to use the CAL API or Brook+ to access that device.
0 Likes

Originally posted by: MicahVillmow The HD4200 is based on the RV620, which does not support Compute Shader.

To use the Stream SDK you need to use the CAL API or Brook+ to access that device.


Well. I have tried to access the device with CAL. I see the info by calDeviceGetInfo/calDeviceGetAttribs

target: R600 ISA
wavefront size: 64
num of SIMDs: 2

Is it possilble ( 64, 2 )?

There are no more detailed information about AMD 785G chip internals found by me (too many names RV620, RS880, 785G and too many brief info about), but i have another info : AMD 785G chip has 40 unified shaders, in comparison with known hdxxxx they must be done as 1 SIMD = 8 thread processor * 5 cores (4 float/int cores or 1 double core and 1 transcend core and|or branch) and 8*4=32 is wavefront only.

Where can i get more info about RS880 internals for test purposes?

0 Likes

grizlyk,
All that really matters from the stream sdk perspective is the graphics core type, in this case the RV620. RS880 and 785G is the code name and product name.
More information can be found here:
http://en.wikipedia.org/wiki/C...8HD_3xxx.2C_HD_4xxx.29
0 Likes

Is it possilble ( 64, 2 )?
I want to say, that CAL for the HD4200
1. does not known IGP (uses as HD2400 compatible)  
2. _probably_ returns wrong number of SE/wavefront size (no HD4200  details)

Is it possible to execute CAL programs with HD4200 if the hardware can not be detected by CAL properly?

0 Likes