Erratic Core clock Speeds and worse performance when overclocking.

[iB CoMpL3XiTy]

Hi all,

I thought I'd have a go at the Tomb Raider benchmark (and post up my results in the TR Benchmark results thread), however I've noticed two odd occurrences.

1) If I have MSI AB (3.0.0 Beta 18) open whilst benchmarking and change no settings at all then my results are worse then if MSI is closed whilst benchmarking.

Without MSI AB: Min = 56.3, Avg = 70.1
With MSI AB: Min = 50.5, Avg = 67

2) I overclocked the cards to: 1050mv, +20PL, 950cc, 1352mc and ran the benchmark again, this time my results were: Min = 45.3, Avg = 64.4

I noticed that the core clock frequency is all over the place (see screenshot in spoiler)

Spoiler

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It seems like some kind of throttling to me but temps are good with the cards at 40C and CPU at 52 max.

Core i7 3930K 4.5Ghz HT Off
2 x 7950's in CF
Seasonic 860W
Custom Water
.....

Any idea's guys

 

[Rasch]

Use and older version of AB

 

[old gamer]

As much as I like ab for its osd function I find trixx much more stable for overclocking

 

[Five.Stars]

As much as I like ab for its osd function I find trixx much more stable for overclocking

+1

Try Trixx with RadeonPro for OSD.

 

[Five.Stars]

Also those scores seem very low with 79 series crossfire, assuming you are at 1080p?

 

[Davedree]

if you do use trixx then be aware that there is a board tdp slider its hidden under Vddc,
Use the grey vertical slider to the right to scroll down,

The amount of people that are caught out by this is funny.

 

[iB CoMpL3XiTy]

Ok, so I've been overclocking with Trixx and now the core clock frequency seems to stay at it's correct clock speed (monitored with GPU-Z) so that's all good.

I tested again with my OC settings of 950c, 1352m, 1050mv, +20 and got the following results:
Min = 56.6, Avg = 78

These results seem pretty poor, my minimum frame rate is the same as it is at stock, and my avg is up about 10% which I guess is ok but I expected abit better to be honest.

I'm going to test out some other benchmarks and see if I get the performance improvement I would expect.

Thanks for your help so far guys.

 

[Five.Stars]

Have you disabled ULPS via Trixx? You need to restart after doing so.

 

[iB CoMpL3XiTy]

@Five.Stars, Yeah I had to disable it otherwise it wouldn't allow me to overclock at all.

Tested with Unigine Valley benchmark (1.0) with Extreme HD present @ 1080P

Stock Score: 1892
OC Score: 2170 (970c, 1400m...)

Core increase = 15.4% (bearing in mind my cards come factory OC'd to 840Mhz)
Memory increase = 12%

Score increase = 14.7%
(Hopefully my maths is correct)

That seems fine to me, so I'm not really sure what's going on with my min frame rate in TR when overclocked with Trixx, it doesn't seem to be a problem with Trixx though.

I think I'll just forget about it and just enjoy the game.

 

[Five.Stars]

Hi mate, I just run the Tomb Raider bench at those settings (7970x2, 4770K@ 4.4ghz), clocked the cards to the same speeds as yours 950mhz core and 1352 memory and I get the following results:

Min FPS: 64.0
Max FPS: 108.0
Avg FPS: 88.1

So, given the 5-10% difference in performance between the 7950's and 7970's clock for clock, your results seem fairly spot on. If you can increase your core to 1000ish then you should be hitting the magic 60fps minimum, although you are close enough as it is that it would be doubtful you would notice the difference without an on-screen display.

 

[Zeed]

Mate if you are using 14.1 14.2 or 14.3 drivers.... Go back to 13.12
Its power limit not working and thats why you get lower scores on oc... Reported over 2 months ago and AMD does not give a flying ****.