4870 Overclocking Thread

[skindogg]

The thing is, on the stock cooler, there's that slot next to the right edge where air is getting sucked over the vregs. However on the FC block they are just covered up, but no contact to the block.

I got a slot fan with dual fans blowing up onto the card from right below it, but I think the stock cooler probably cools vregs better than this.

I can't believe the mount was bad since the GPU temps are all in the 40s while gaming.

I guess I was curious as to whether it's ok if the vregs operate in the mid 90s all the time. I'm fine with not running furmark ever. I don't plan on volt modding either.

[Caveman787]

Just because the core is being cooled well doesn't mean it's not bent or something toward the vreg area making not the best contact.

Also I would think the coolness provided by the water and lower core temp would radiate through the block material thereby cooling the vregs better.

You'll be fine in the 90's though as someone else said there spec'ed for 125 degrees celcius.

[Simsons2]

Just first fast run , stock coolin , no mods.

[Rattle]

anyone try upping volts in the profile with positive results? my card is good for 875 on stock volters.

[Simsons2]

anyone try upping volts in the profile with positive results? my card is good for 875 on stock volters.

no artifacts in Ati tool?
Can run 3dmark @ 870 / 4500 , but artifact free core is only @ core 850

[Rattle]

i dont use atitool, but its fur, rthdrbl, 3dmark06 and hours of cod4 and crysis stable without artifacts

[Simsons2]

06 mark is benchable only @ 850 / 4400

[Rattle]

06 at 850/1000, i can run 1100 on the mem but I dont see any difference.

[fatguy1992]

I can only do 825MHz anything else doesn't work - did I get a bad card?

Also I can do 1175MHz on the memory

[M-XXXX]

I can only do 825MHz anything else doesn't work - did I get a bad card?

Also I can do 1175MHz on the memory

My experiences with GS are similar... GPU doesn't clock well!

[fatguy1992]

My experiences with GS are similar... GPU doesn't clock well!

Thx so is not just me

I have my second 4870 GS waiting to go in, but i didn't get a CF bridge with either card. Therefore i ordered one off ebay and it will take a while 2 be here .

Anyway i'm going to put it in too see what it can do

[M-XXXX]

Probably because of only 2 power phases for GPU... I've tested one, and the upper limit was 780, and my sapphire can do 860-870

[Simsons2]

I'm ordering
Thermalright T-Rad 2 soon and getting vcore mod
I hope getting 900 mhz core 24/7 stable

[overclock]

My HIS 4870 1 GB sucks : it is cooled by a phase change cooler, at -38°C (core temperature) and in 3DMArk06, it is stable at 951 Mhz max (1010 Mhz for the RAM). And the games are stable from 895 (Condemned) to 970 Mhz (hellgate). Most of them are stable at 920 Mhz. Pretty bad since I expected a 40 % overclock like my previous 9800 GTX. Here, I obtain around a 20 % overclock. Since the memory IO is far hotter than the core (between 10°C and 15°C more), checked with Riva Tuner 2.11, I assume that the memory controller is limiting my overclock ability. Since it is a 1 GB card, the memory controller might be stressed more than with 512 MB ?

I will sell it and buy a 4870X2 instead. I don't want to buy a second 4870 1 GB and obtain such a crappy overclock again.

[Nazu]

What kind of temps are you getting with the stock cooler? Core 750@800MHz and 67-68 at load and the VDDC temps are 112-113. The fan is at 100% speed.

edit. Ah, nvm already found one...

[SNiiPE_DoGG]

My HIS 4870 1 GB sucks : it is cooled by a phase change cooler, at -38°C (core temperature) and in 3DMArk06, it is stable at 951 Mhz max (1010 Mhz for the RAM). And the games are stable from 895 (Condemned) to 970 Mhz (hellgate). Most of them are stable at 920 Mhz. Pretty bad since I expected a 40 % overclock like my previous 9800 GTX. Here, I obtain around a 20 % overclock. Since the memory IO is far hotter than the core (between 10°C and 15°C more), checked with Riva Tuner 2.11, I assume that the memory controller is limiting my overclock ability. Since it is a 1 GB card, the memory controller might be stressed more than with 512 MB ?

I will sell it and buy a 4870X2 instead. I don't want to buy a second 4870 1 GB and obtain such a crappy overclock again.

Well you can't compare percentage overclocks 1:1, Nvidia architecture tends to scale to higher frequencies with less gain. I think if you did a performance scale comparison you would find that the cards overclock about the same. Its a shame you cant reach for 1ghz @ benches. I think the Issue is OVP @ 1.5v on these cards although we don't want to start killing them.

[Nazu]

Looks like I got a crappy oc'er again. Can't even do 950MHz on the mem without furmark crapping out and drivers giving a vpu recover. Core seems to do 820MHz but that's with the stock cooler 100% speed. Somehow I'm getting the feeling that the overclocking is much easier with the Nvidia cards...

[overclock]

Well you can't compare percentage overclocks 1:1, Nvidia architecture tends to scale to higher frequencies with less gain. I think if you did a performance scale comparison you would find that the cards overclock about the same. Its a shame you cant reach for 1ghz @ benches. I think the Issue is OVP @ 1.5v on these cards although we don't want to start killing them.

With a 2900 Pro 1 GB, watercooled by a waterchiller (water temperature = 15°C), I had reached 900 Mhz at 1.15 V and 990 Mhz at 1.35 V.

Here, I reached 900 Mhz under phase : even compared to the 2900 Pro card, it is disappointing. And 2900 cards are famous for heating much.

[twwen2]

I've had my geCube 4870 512MB for a few months now, and just installed it in a new vista system.

I had been running the Asus top bios (gpu=815 mem=925) which got me around 14.5k in 3dMark06, default settings.

Today i used RBE1.13 to mod the bios, and flashed it succesfully to gpu=850, mem=1000. The flash worked, and after a reboot GPU-Z reported everything correctly, along with the increased bandwidth (128GB/s).

However, i ran 3dMark06 again, and now the score has dropped to 11k.
Nothing else was changed, the tests were run back-to-back (before and after flashing).

CPU is E8600@4GHz, the rest in my sig.

Anyone got any ideas as to why my score dropped so much???

[alexio]

I've had my geCube 4870 512MB for a few months now, and just installed it in a new vista system.

I had been running the Asus top bios (gpu=815 mem=925) which got me around 14.5k in 3dMark06, default settings.

Today i used RBE1.13 to mod the bios, and flashed it succesfully to gpu=850, mem=1000. The flash worked, and after a reboot GPU-Z reported everything correctly, along with the increased bandwidth (128GB/s).

However, i ran 3dMark06 again, and now the score has dropped to 11k.
Nothing else was changed, the tests were run back-to-back (before and after flashing).

CPU is E8600@4GHz, the rest in my sig.

Anyone got any ideas as to why my score dropped so much???

You could decrease the vRAM clock and if that doesn't work decrease the GPU clock. GDDR5 has a very strong mechanism for correcting errors so it can clock very high but clocked too high it will be slower because packages have to be re-requested () and resend.

[twwen2]

You could decrease the vRAM clock and if that doesn't work decrease the GPU clock. GDDR5 has a very strong mechanism for correcting errors so it can clock very high but clocked too high it will be slower because packages have to be re-requested () and resend.

Right!
I just learnt something, thanks!

I couldn't comprehend how an increase in clocks could possibly lead to less performance, but that makes total sense.

It is slightly dissapointing, seeing as the ram is rated at 1000MHz.

[twwen2]

Hmm, well i downclocked to 850/950, and the score dropped another ~150 points. Then i tried 820/950, still the same. These were all modified versions of the Asus "Top" bios, using RBE1.13.

After flashing back to the origional asus top bios (815/925), my score has jumped up to 15,171! That's even higher than before!!!!??? There was nocitably more FPS in every test (i'm talking an extra 25-30fps), even the two CPU tests were faster.

I'm at a loss!
Downclocking FTW!?

[alexio]

Hmm, well i downclocked to 850/950, and the score dropped another ~150 points. Then i tried 820/950, still the same. These were all modified versions of the Asus "Top" bios, using RBE1.13.

After flashing back to the origional asus top bios (815/925), my score has jumped up to 15,171! That's even higher than before!!!!??? There was nocitably more FPS in every test (i'm talking an extra 25-30fps), even the two CPU tests were faster.

I'm at a loss!
Downclocking FTW!?

What happens when you overclock with the standard BIOS? It could be that the performance profiles were messed-up in the TOP BIOS or that the driver had problems with that BIOS somehow. Just remember that it's not a good idea to use a BIOS with different vRAM frequencies in different profiles. You'll get a weird switching effect when running 3D benches.

[twwen2]

What happens when you overclock with the standard BIOS? It could be that the performance profiles were messed-up in the TOP BIOS or that the driver had problems with that BIOS somehow. Just remember that it's not a good idea to use a BIOS with different vRAM frequencies in different profiles. You'll get a weird switching effect when running 3D benches.

Yeah i always kept the ram the same frequency in all profiles.
I've never tried overclocking the factory (geCube) bios, maybe that's worth a look. Is 15k in 3dMark06 about right for a system with my specs?

[Aberration]

I still need to do more testing, but anything over 1000MHz on my Sapphire 4870 1GB results in instant artifacts. But at 1000MHz there are none in ATi tool for hours.

I need to edit the BIOS though to get above 790 on the core, as it handles that with ease.

Using a MCW60-4870.