Why is my 5870 Bandwidth is only 116.2GB/s?

[nytrus90]

Hey

as the title states in GPU-z my bandwidth is only 116.2GB/s when it should be something like 153.XGB/s.

But when I go into ATI's CCC in Graphics Hardware it states that the bandwidth is 153.XGB/s but GPU-Z reports different why is this?

also in benchmarks my 5870 is on que and does not seem to have any major FPS difference when compared to other peoples 5870s

so do you guys think its a bug or do i have an issue here?

Kind Regards

Nytrus90
-----------------
the rig

windows 7 64bit
phenom 955 @ stock
antec 850watt
XFX 5870
geil 4GB DDR3 @ 1333mhz
Asrock 790GXH/USB3 mobo

 

[shadow187]

3 x PCI Express 2.0 x16 slots (green @ x16 mode, blue @ x8 mode, orange @ x4 mode)

Make sure your card is in the green one.

 

[strangestranger]

He is referring I would imagine to the memory bandwidth.

OP, most likely gpu-z is using the lower, idle clocks of the ram to work out the bandwidth while the ccc is using the full clocks.

The ccc only reports the bandwidth with 3-d not 2-d clocks.

 

[nytrus90]

Thank you strangestranger for your reply.

going by what you said, should i not be worried?

also, when looking at other peoples GPU-z result for the 5870 (like tributor) his GPU-z shows the full memory bandwidth of 153.xGB/s

ive tried running a windowed benchmark ( heaven) then boot GPU-z but still clocks it as 116.2GB/s

Kind Regards

Nytrus90

 

[strangestranger]

Hi, best thing to do is just work it out yourself to put your mind at ease.

Run gpu-z and log it while playing the game. Then look to see if your ram speed increases when the game is running, best make sure it is in full screen mode. If it does, then you will know the card is running properly as the bandwidth is calculated by the frequency of the ram multiplied by the bit width which I believe would be 256 for the 5870.

Also note that due to the use of gddr5 you will have to multiply the frequency by 4 for the effective clock speed.

This should help make sure everything is working fine.