HD7000 Series VRAM Overclocking Benchmarks - a "memory hole" at 1300MHz?

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BoFox

Senior member
May 10, 2008
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Wow, now it looks like the timings have been loosened not just once, but twice!

I wonder if you could check the BIOS clock tables and see if there's anything to indicate this type of behavior with the timings - if it has information on the timings?

Not sure if Sisoft Sandra can check into the timings - it's probably only with the older video cards that gave polling information on such.
 

pandemonium

Golden Member
Mar 17, 2011
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This is very interesting. Now I'm curious to find if there's any dips instead of straight scaling. Though, I'm not running anything near 1300mhz on memory since I'm using older architecture.

Moar testing/tweaking! Wee. :D
 

Yuriman

Diamond Member
Jun 25, 2004
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I ran Unengine Heaven 4.0 and saw nothing like that on my 7850, but it's possible that Heaven just isn't very memory bandwidth hungry. I'm not looking forward to running 3dmark 8 times because it's such a long suite.
 

Termie

Diamond Member
Aug 17, 2005
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I ran Unengine Heaven 4.0 and saw nothing like that on my 7850, but it's possible that Heaven just isn't very memory bandwidth hungry. I'm not looking forward to running 3dmark 8 times because it's such a long suite.

Thanks for checking on that. You could also try the older 3dMark11, which doesn't take as long to run as 3dMark 2013.
 

Rikard

Senior member
Apr 25, 2012
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you should also test frame latency (stuttering).

the avg fps may be going up, but at an expense in smoothness.

I actually started the benching with frame time recording using Fraps, but the results were obviously nonsense. Fraps claimed that there were >2 s freezes every now and then, which I can assure you was not what the screen was showing. Not sure what went on there, probably some limitation of bug of Fraps giving those false positives.
 

Termie

Diamond Member
Aug 17, 2005
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I just put together a chart illustrating similar testing on my GTX670. It doesn't show any dips, but it does have notable plateaus at 6300, 6600, and 6900, and then really begins to cap out after 7000.

capturecdc.jpg


By the way, overall score scaling from 6000MHz to 7200Mhz is around 22%, basically identical to my HD7870's memory scaling.
 
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hyrule4927

Senior member
Feb 9, 2012
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I collected some more data for you. Pardon the badly formatted plots.

GraphsBetter_zpseef699fc.png


Looks like I've been underestimating the overclocking potential of my memory for a while.

Edit: Made the font a little bigger.
 
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Termie

Diamond Member
Aug 17, 2005
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I collected some more data for you. Pardon the badly formatted plots.

...

Looks like I've been underestimating the overclocking potential of my memory for a while.

Great data! I will add it to the OP. It looks like you have a dip between 1300 and 1400, much like my card.

I took the liberty of calculating memory scaling for you, and it came to about 18%, similar but slightly lower than both my HD7870 and GTX670. That makes sense - the 384bit bus means the card simply isn't as starved for memory bandwidth.
 

3DVagabond

Lifer
Aug 10, 2009
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I just put together a chart illustrating similar testing on my GTX670. It doesn't show any dips, but it does have notable plateaus at 6300, 6600, and 6900, and then really begins to cap out after 7000.

capturecdc.jpg


By the way, overall score scaling from 6000MHz to 7200Mhz is around 22%, basically identical to my HD7870's memory scaling.

If I could be a PITA might you try checking frame latencies as well to see if there's any increase when the memory takes a nose dive?
 

Maragark

Member
Oct 2, 2012
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I noticed something similar while mining with my 6870 but on the lower end of the scale and other people reported the same thing on their 58xx and 69xx card. On my 6870, 200 MHz was the sweet spot and below that performance dropped rapidly.

You should underclock the memory to complete those charts and maybe talk to some of the bitcoin miners as well. I'm sure they'll have something to contribute on the issue.
 

Lonbjerg

Diamond Member
Dec 6, 2009
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Wasn't there something like this back on the GT6800 seies...or was it the 9800(ATi)?