Radeon 7950 boost voltage...

[PowerPie5000]

I've only just noticed that my Radeon 7950 core voltage hits 1.25V when it boosts to 925Mhz! Isn't this a bit excessive for only 925Mhz? The card i'm using is a HIS Radeon 7950 IceQ Boost Clock edition... It also seems other 'boost' cards hit 1.25V after doing a bit of reading, not just HIS branded ones. Should i be worried about the cards lifespan with these high voltages?

[Willzzz]

I don't think it's really going to impact the lifespan of the card, at least not before you'd want to replace it anyway.

http://www.anandtech.com/show/6152/a...950-with-boost

"Meanwhile the boost voltage goes much higher, with AMD using a rather high 1.25v for the 925MHz boost clock. In fact this ends up being the highest voltage a reference Tahiti card operates at, as even the reference 7970GE only used 1.218v."

Basically there's no such thing as a free lunch. The boost uses the extra voltage to deal with the worst case scenarios, most cards shouldn't need it, but they are playing safe.

Trouble is of course that the extra power means that the cards throttle back quite quickly and the boost is almost never sustained for long. You are probably better off doing regular overclocking on a regular 7950 that way you can find the sweet spot without having to use quite as much voltage.

[PowerPie5000]

I'll probably keep this card for the next 2 years or so (had my 6870 for 1.5 years)... Maybe there's a way to reduce the boost voltage? I've no need to overclock this card anyway . I've also noticed that GPU-Z reports the VRM temps as 24C all the time (never higher or lower)... I wonder what's up with that?

[PowerPie5000]

I used the HIS iTurbo utility to try and lower the boost voltage, but it doesn't seem to change! It lowers the voltage for the cards normal 850Mhz operation speed, but it still reports 1.25V when it boosts (925Mhz). I wonder if the bios can be flashed using a non-boost 7950 bios? I still think 1.25V is too high for just 925Mhz (people get over 1000Mhz with less voltage).... GPU-Z ASIC quality reads only 65.5% for this card at stock settings

[Willzzz]

Yeah you might be able to flash it back to normal operation.

Or maybe it won't "boost" if you set the default clock to 925mhz or more.

[PowerPie5000]

All OC utils seem to think the boost speed (925Mhz) is the default core speed for some reason. The same applies to CCC and GPU-Z etc...

[PowerPie5000]

OK, it runs stable at 1100Mhz without breaking a sweat and it seems to stay like that (no boost)... I won't be keeping it overclocked as there is no need (and i don't want to ruin it in the long run ). As for the voltage, it seems to be locked as it still runs at 1.25V under full load no matter how many times i try and change it. I suppose 1100Mhz isn't too bad for a GPU with a 65.5% ASIC quality score

[PowerPie5000]

I realised something... Changing the voltage using any OC util (Afterburner, Trixx, iTurbo etc.) only works when the card is running at it's default clock speed of 850Mhz (basically non-boost mode). The 925Mhz boost will always spike upto 1.25V and i don't see any way of changing this until it gets added into any of the OC software. Overclocking the card basically bypasses the non-boost mode, so it will always run at 1.25V if overclocked.

Whoever designed the boost bios must have had their head up their arse! The only way i can change this is to possibly flash another bios which would definitely void the warranty (luckily my card has a dual bios switch in case it bricks)... A Radeon 7950 running at 1.25V is sure to die a quick death compared to the lower voltage, non-boost versions! The VRM temp sensors seem to be fudged too as they constantly read 24C and don't budge... The fan also runs loudly at 100% for around 6-7 seconds when i switch on the PC (these reasons are probably not enough to RMA it though ).

[PowerPie5000]

Ok this card pretty much stinks now! I've been running it at stock settings and it doesn't seem to cope well with long gaming sessions! BF3 started to glitch after 4 hours and the card was emitting a slight electrical buzzing noise and a faint burning smell (similar to burning plastic). It started squealing like mad when i first loaded up Crysis 2 (although it's stopped doing it at the moment )... STALKER: Call of Pripyat causes this card to squeal loudly and erratically (buzzing and squealing at different volumes!)... The game also stutters like mad and glitches, but the worst part is GPU-Z reported a core voltage of 1.438V when running this game !

I thought this card was brilliant when i first got it 2 weeks ago, but i've only properly used it all day today and find it doesn't cope too well . I always thought HIS were a decent brand, so i guess i must be unlucky as this card is definitely not right.

[CAT-THE-FIFTH]

That cards sounds like it needs to be RMAed!! It might be worth going on OcUK as there should be some more HIS HD7950 owners over there,to see whether it is a common problem or not.

[PowerPie5000]

That cards sounds like it needs to be RMAed!! It might be worth going on OcUK as there should be some more HIS HD7950 owners over there,to see whether it is a common problem or not.

OCUK is where i got it from, and i've discussed it on their forum but there doesn't seem to be anyone with the same model . I've put in an RMA ticket with OCUK... I just hope they get the same issues when they test it! I've even tried it in my partners PC and it had the same issues (her GTX 660Ti works flawlessly in my PC with no noise coming from anywhere at all, so i know my PC is not the problem ).

I've had it for about 2 weeks now so i wonder if they'll exchange it or refund it? I might try the same model again as they don't really have a good selection of 7950's over there.

[PowerPie5000]

I can't believe OcUK have declared my card card as not faulty! It's definitely not right as i've tested it in 2 machines with the same results! They didn't even test it with the games i mentioned either .

This is the response i got:


"Graphics Card posts through all outputs with no issues at all, ran the card through Furmark, MSI Kombuster, Resident Evil 5 & Heaven Benchmark and there were no issues, Graphics card working fine, pl"


Of course it still runs games, but it gets pretty damn noisy (mostly squealing and sometimes buzzing), the VRM sensors are borked, the voltages are too high and it gets glitchy with some games after a few hours of use! I've been running a GTX 660 Ti in my rig with absolutely none of these issues (and my previous 6870 had none of these issues either).

I certainly don't want to be paying any test or return fee's as i no longer want it and would prefer a replacement (same model)... If it was working fine then i wouldn't have gone through all the hassle returning it (at my expense i might add). I wonder where i stand with the SOGA?

[EIma]

925Mhz is the default core speed

[PowerPie5000]

925Mhz is the default core speed

925Mhz is the boost speed. The default core speed (non-boost mode) for this model is 850Mhz (which is still 50Mhz faster than a reference 7950).

Anyway, i RMA'd this card again with OcUK and they sent me a replacement which is perfect! No more coil whine and all the temp sensors are working properly . The boost voltage is still a bit high imo, but it seems to handle everything just fine and the core temp never tops 61C which is great .