can you beat my clock? (hd5850)

[spudhed]

most proud of my new clock on my sapphire hd5850, but im interested if anyone has beaten it and if theres a chance i can squeeze a little more out of it, i so want to take that top spot on the hardware chart (currently second) my current clock is: core: 1000mhz, memory: 600mhz (crashes any lower) vcore 1.231, over 24hours stable so far pumping out 400.17MH/s on stock cooler at 77c max. the main thing im interested in is just how much voltage these things will take before i blow its head off, would 1.300v be a step too far?

[mike678]

http://forum.bitcoin.org/index.php?topic=24949.0

records 432.5 see page 5

[spudhed]

bah and i just noticed that sapphire trixx wont actually let me push it any higher than 1000mhz (i have to use trixx as nothing else will oc my voltage as its a non ref card) looks like im at my limit, im still fairly happy with the result but im sure there would be more there if the app would let me

EDIT

ok so a little more with the new kernel tweaks, running 403.97MH/s now

[Dargo]

Nice job, that is an impressive hash rate. 5850s are sweet, no? I've had my Sapphire 5850 up to 380 Mh/s with stock voltage using phoenix/phatk and clocks at 950/300. I actually haven't found the upper clock limit on the Sapphire, but I doubt it will go much higher than 950 at stock voltage. My other XFX 5850 is stable at 925/425 (350 Mh/s), but doesn't like to go any further. I know it's cool to "win" on your hash rate, but given how hard it is to find 5850s these days at a good price, I personally am more concerned about longevity than maxing out my hash rate short term. I definitely wouldn't try 1.3 voltage, unless you can confirm that your VRMs are running cool at the current voltage (they are probably running really hot already though).

[spudhed]

yeah i think im now maxed out, luckily sapphire 5850s arent hard to find for me, a local supplier has bucketloads in and is selling them at £120 a piece, i know as one of my friends bought 6 of them this morning at my reccomendation (after ignoring me first time and insisting that the xfx 5870 would be better for his first two cards, his max 399mh per card) ill be clocking them up later this evening, itd be nice to get em all up to 1000mhz

as for cooling im running case open with the stock cooler and 2 120mm fans pointing at the back of the card, i have no way to actually test it but it sure feels cooler than my 4850 does at stock, hope im not going to cook it, id clock it down if i wasnt so happy to see that 400mh there, maybe ill add more cooling soon just to be on the safe side. oddly mine got nowhere near 950 on stock, more like 870 before i had to up the juice, but ive been gradually increasing it since i got the card and it hasnt shown any real signs of dying yet (bsods, reboots, vpu recovers etc) i just like to get the most possible bang for my buck if you will, especially as i cant currently afford to add another card to the mix, hell im currently too broke to afford a 1x to 16x riser for the 4850 but i may just do that the pikey way and dremel out the back of a 1x slot so it fits

[Dargo]

Nice, you are lucky to have a 5850 supplier. I found two @$149, but that was just a matter of blindly stumbling upon a local (Southern Cal) supplier that happened to have two new open box cards. You are probably OK with your current settings, but from what I have read, your card can appear to be running quite cool while the VRMs are actually frying. If you don't have VRM sensors, the only way to tell for sure is with a heat gun. And I'm not sure to what extent air cooling will help those VRMs. If you don't want to buy a heat gun, maybe the thing to do is track down someone on this board with more technical knowledge than myself and see whether this person thinks you are safe running your current settings long term. It would suck to fry those 5850s and not be able to afford to get any more...

[spudhed]

a heat gun? do you mean some sort of thermometer? i already have a hot air rework station and soldering station so im well prepared should something blow, it was running at 950mhz at 1.182 before and had run for a good few weeks without an issue but my core is running 10c hotter since my latest voltage push, at any rate technically the card has already paid for itself so if it does blow im sure i could get another somehow if i cant revive it (luckily im very good at zombifying tech, ive brought more xboxes, ps3s and laptops back to life than most doctors have with patients, its how i get a lot of my tech being the penniless bum that i am, buy it broke and fix it)

and i did used to work at said supplier so i would have gotten them even cheaper back in the day, but while theyre cheap to buy from, theyre awful to work for. and they have actually put the prices up recently, when i bought my card i got it for £99.99 wish id known what a bargain it was at the time, id have bought another

[Dargo]

Sorry, "heat gun" is misleading. What you want is an IR gun - you just point it at your cards and it will give you temp readings. Supposedly they are pretty cheap. See the link to the thread posted by Mike above for a screen shot of the info it can give you. Again, you are probably OK, but personally if I were overvolting, I would want to know how hot my VRMs are just to make sure the cards will last for a while. But maybe I am too cautious. =)

[spudhed]

no i think its that i shouldnt be so carefree, but that comes from being able to fix most things that i break, i do think im going to look into some extra cooling though, maybe make a heatsink of some sort and some extra fans for the back. ive pumped staggering voltage through both cpus and ram but im not so au fait with gpu overvolting at the top end, or i wasnt until i started this lark!

i have used my laptop before, not clocked but ive mined with its whole 11mh/s power and it gets mighty hot and it crashes when you close the miner but it still lives (gpu temp 99c!)

[Dargo]

Here is a quote from the thread linked above:

"While 1000 was stable at 1.149v, I had to up to 1.162v to hit 1010MHz on the core.  The VRMs were a bit scary though, nearing 115c.  This was only for a few minutes too; probably won't feel comfortable until I get that new thermal stuff in."

So here is someone whose VRMs were at 115c@1.162v. So, yeah, I'd want to to know what my VRM temps are at the voltage you are running before going with this long term. Since I can already get to 950 stock, I'm curious now what a little overvolting will do. I also noticed that there is someone in the thread talking about pointing fans straight at the VRMs to manage temps, so that might work. You might even be able to fit some heat sinks on the VRMs under the stock hood (though on my non-reference Sapphire there doesn't look to be much room between the top of the VRMs and the hood).

[spudhed]

if youre getting 950 on stock a little push should easily take you to the magic 1000mhz, as i said ive got 2 120mm fans pointing at the back of the card for a bit extra cooling, im currently trying to get the techpowerup tool working on my card to tell me the vrm temps, but i fear i may be better off not knowing and i really need to find a way to get that memory down, 600 is just too high but it seems to crash any lower

EDIT

YES!!!!! down to 300mhz worksize up to 256 and now getting a clean 410MH/s

[Dargo]

410 - nice! I'm starting to think 5850s are a much better buy than 5870s if 400+ is safe and stable on the 5850s. I guess I missed the part about having fans blowing on the back of the cards, that is good. I'm definitely going to give overvolting a try when I get the chance. I'm running linux atm, though, so I think it will be more of a job to change the voltage settings. BTW, since you fix your own stuff, how hard would it be to replace the VRMs if they do blow (assuming no other damage to your card)? My guess is that it isn't very hard so long as you have the tools and the know-how. Let us know if/when you get the VRM temps.

[spudhed]

i cant say ive looked too hard but i cant imagine theyre much more difficult than some of the tiny stuff ive done on consoles, my old sat cam mods and phones before so long as it doesnt kill a bga chip or something it should be salvagable, will let you know on the vrm temps as soon as poss but the system is now in use for watching movies (yep im amazed that it runs movies while mining too, it doesnt even slow it! oddly iexplore doesnt fare so well)