5870 Crossfire : Keep i5-750 at stock or push it ?

[finndrummer]

Hi guys
Tomorrow i will get my second 5870 (XFX 5870 XXX Edition 180€ from a friend) so i just want to know if i have to push my i5-750 to 3.6-3.8 (already stable at 3.6) or leave it at stock (2.66, 2.8 turbo) without bottlenecking ?
I will also upgrade my monitor to 24" FullHD.

 

[sneekypeet]

IIRC 3.6Ghz was achievable on or near stock volts. I say if it is stable and you arent having to push the voltages, I'd leave it clocked.

 

[TIGR]

The 750 is already plenty fast at stock clocks to run many games at max settings with a more than playable frame rate—but it really depends on the games and settings you're running. There is such a difference based on these two variables that I think the best way to decide will be to test your games and settings with and without the overclock and figure out whether it's worth it to you.

For the sake of heat and power consumption, I suggest you select the minimum settings (clocks and voltages) that provide your desired level of performance. For example, if CoD4 were the most demanding game you played and at your preferred settings it ran at 100FPS on stock clocks, you'd just be wasting power and generating excess heat by overclocking.

 

[finndrummer]

Really heat and power consumption are some important things that i consider. and yeah 3.6 is achievable without tweaking, i think like TIGR says, test every game if it needs more cpu power, if i remember, splinter cell conviction were the only game where i had to push my cpu to 3.6 to have better playing and with stock all my tested games runs good.

 

[finndrummer]

one card is overclocked and another stock, how will they sync ? no problem ? or i have to put the xfx to reference stock ?

 

[dir_d]

id put them at the same clocks for max performance

 

[yogurt_21]

dude this is like going to a bar and asking whether or not you should drink. Of course you should push it, and while you're at it, have a beer.

 

[cdawall]

the driver will drop the xfx to stock clocks

 

[cadaveca]

the driver will drop the xfx to stock clocks

No, it won't. Crossfire only adjusts memory size to match. You could clock one card @ 300mhz, and the other @ 3000..wouldn't matter. Although I think both cards at the same speeds may lead to less cpu utilization as the driver doesn't have to load-balance as much.


Also, I find about 3,6ghz good for crossfire...for single card, whatever the app says is minimum frequency for it, should be OK(given about avg 3ghz or so nowadays).

Crossfire has more driver overhead, hence requires more than singlecard.

 

[slyfox2151]

No, it won't. Crossfire only adjusts memory size to match. You could clock one card @ 300mhz, and the other @ 3000..wouldn't matter. Although I think both cards at the same speeds may lead to less cpu utilization as the driver doesn't have to load-balance as much.


Also, I find about 3,6ghz good for crossfire...for single card, whatever the app says is minimum frequency for it, should be OK(given about avg 3ghz or so nowadays).

Crossfire has more driver overhead, hence requires more than singlecard.

are you sure? do you have a source... or official documentation...


i have always herd that Speed, Ram and shaders will be droped to the lowest cards..... so if you had a 5830 and a 5850... it would turn the 5850 into a 5830.

 

[Mussels]

No, it won't. Crossfire only adjusts memory size to match. You could clock one card @ 300mhz, and the other @ 3000..wouldn't matter. Although I think both cards at the same speeds may lead to less cpu utilization as the driver doesn't have to load-balance as much.


Also, I find about 3,6ghz good for crossfire...for single card, whatever the app says is minimum frequency for it, should be OK(given about avg 3ghz or so nowadays).

Crossfire has more driver overhead, hence requires more than singlecard.

^ what he said, clocks can differ on ATI. its only nvidia that require them to be the same.


i too am confident that more GPU's requires more CPU power, so OCing may be needed to get the full power of your GPU's.

 

[cadaveca]

are you sure? do you have a source... or official documentation...

I've been running dual ATi cards since X800 days, and have clocked my cards at different speeds pretty much until these cards I have now, which aren't overclocked at all. I can confidently says that is how it works, and I can also says that shaders DO NOT adjust in size as well, and I'm sure any 5850/5870 Corssfire user(there are at least two here on TPU) can confirm that.


Sli, however, is different.

You can even run 5850 bioses on 5870's, and vice versa...and shader amounts will not change. If bios cannot change this, then for sure, software cannot as well.

Load balancing might make for less utilization of the card with more shaders...I'll have to take a look into that one. Crossfire doesn't work with 5870 and 5770...the requirement is purely the same base gpu is used.

 

[finndrummer]

so better leave them like they are ? i think also on flashing the xfx with my asus bios ?

 

[cadaveca]

Bios flashing is fine, as long as your card matches the one the bios came from. If both of your cards are physically identical(power delivery section/output varies), you could run whichever bios you like.


To me, you'd think the card connected to the monitors would have to sum the frames together, so maybe having the overclocked card as main card might work best...

In the end, the actual performance difference between overclocked cards and "stock" cards is quite minimal, so unless you are going up to 1000mhz on the gpu or something, I see little point to adjusting speeds in any instance.

In such a way, that my system is barely overclocked...i just don't need the extra power consumption for less than 5 FPS.

 

[finndrummer]

Bios flashing is fine, as long as your card matches the one the bios came from. If both of your cards are physically identical(power delivery section/output varies), you could run whichever bios you like.

how have i to check ? i also flashed many gpu in the past without any precautions

 

[cadaveca]

visually, xfx reference has the fan at end, non reference has the fan in middle.

I do belieive asus labelled non-reference as V2, so you'd know...heatsink design is VERY different from any other 5870 card out there.


So, I have 2x XFX XXX...they did not run 1300mhz mem. XFX directed me to flash bios on both cards, one worked OK, one they replaced(was throttling). New bios is 900/1250 clocks.

The ASUS card should do the 900/1250 clocks as well...so running that bios is of no issue. Likewise with the ASUS bios, if you have reference cards.

I tried running 875/1300 and 900/1250...900 actually seems a bit faster, but not really, mind you, I've got three monitors plugged in. I do know that the 900/1250 bios leads to far less issues for me when @ desktop(although my cursor will "artifact" from time to time).

 

[finndrummer]

i have both reference, the asus is at stock 850/1200, running the xfx xxx with those clocks can lead to stability at 2d ? my friend also says that he had problems with the cursor but the last catalyst fixes it

 

[cadaveca]

I still have cursor issues, for sure. It varies which monitor it happens on...either one specific DVI port, or the DP one. With the latest driver it will magically fix itself about 9/10 times, although I still have to reboot to fix it sometimes.

No magical fix to 2D problems yet(at least for me)...I have tried every bios with just about every driver there is. It's really seems to be hardware related...

To the point that I cannot wait for new cards. i hope that they fix it with the next gen...kinda sucks that I'm not happy with eyefinity, but oh well. The cursor issue is a deal-breaker for me. tier lsit fo "working" apps is frustrating as well....DP connections...still lose monitor on DP at times...

I can say, that single monitor works quite well...I often switch between 3x1920x1080 to 1x2560x1600, in such a way iwish it was jsut possible for me to connect all 4 then then mount all 4 on arms so I can switch with ease...I only like eyefinity for a few titles so far.

 

[finndrummer]

hope i will not get some annoying problems.

 

[cadaveca]

I hope so as well.

There MUST be some users out there without any issues, but of course, they'll not be looking for fixes when everything works as it should.

 

[finndrummer]

just flashed the XFX XXX to Asus reference bios, no problem so far.