Ati hd 3870 and 3850 lag

[Blair Eudy Jr]

I currently Crossfirex-ed My Ati radeon hd 3870 Asus and Ati radeon hd 3850. It now stutters but is far more efficient it terms of my game doesn't freeze for a few seconds anymore but the stutter is constant. I've also noticed in my lower end games that had steady frame rates no jump up and down( like it used to be steady 60-63 fps and now it drops down to about 35fps every about 5seconds). it doesn't stutter like the higher end games i like to play(fallout new vagas and star trek online). but the higher end games don't stutter but a little bit when loading terrain and other stuff when its trying to catch up(it's mostly smooth on any graphics mode low/medium/high just the load here and there mostly). I've been reading about the stutter problem alot on searches and was wondering if there may be a fix for it.

and I read that i need more amps on my 12v rail, 36 compared to the 18amps i have. oh and none of it it over heating, i only have the 20 pin connected for mobo power cause it won't boot with 24pin. yes the extra 4pin is plugged in. sry for the jumble of info but i want to be precise as possible for anyone trying to help.

My system isn't high end but here it is
Mobo - Asrock b75m R2.0 not the dgs
CPU - Intel G630 not overclocked
GPU - Asus 3870 and ATI 3850 not overclocked
RAM - 2x 4gb pc3 10600
PSU - 525watt 18amps on the 12v rail
HDD - 3xSATA none solid state and DVD dual layer burner

 

[clutchc]

You're really pushing the PSU with those two cards. I'm surprised it hasn't shut down on you. The HD 3870 maxed out is a 106W card (8.8A @ +12V) and the smaller HD 3850 is a 75W card (6.25A @ +12V). Not monsters, but quite a bit for a 525W(?) PSU with a single 18A rail. Your processor is another 65W maxed out (5.4A), and the MB may be another 35W (2.9A). You're doing pretty good.

If the cards are actually getting all the power they need, your issue is no doubt the AMD micro-stutter issue with CF. They just released a new driver that is suppose to eliminate most of the m-s. But I don't think it is for any cards older than the 5000 series as of yet.
http://support.amd.com/us/kbarticles/Pages/AMDCatalyst13-8WINBetaDriver.aspx

If games you used to play comfortably are suddenly stuttering, it might be your system needs cleaning. Try running CCleaner and do the Clean and Registry both. http://www.piriform.com/ccleaner
Maybe uninstall the driver, run Driver Sweeper from safe mode and have it remove any AMD, ATI, and Nvidia graphic driver remnants it finds. Then reboot and install the latest driver for your card(s) from the website.
Driver Sweeper: http://www.techspot.com/downloads/4266-driver-sweeper.html
AMD Graphic Drivers: http://sites.amd.com/US/GAME/DOWNLOADS/Pages/downloads.aspx

Btw, your MB's 2nd PCIe X16 slot is only x4 electrically. That alone will drag down the performance of the card in the x16 slot. You may want to think about selling those two antiques and getting a single faster HD 7xxx in their place.

 

[Blair Eudy Jr]

i knew the second slot was only 4x but i didn't think it would hurt the performance of the first card, i thought it just wouldn't give me as much of a boost in graphics. I had a friend who wanted the old ram sticks i was using and was willing to pay me more than the new board which is why I got it cause i had the stuff to put in it just laying around not being used cause the old board was fried. I don't have the money for any new parts is why i got the board to upgrade and be able to use the 2 cards, but he said he has an hd 4870 that he's not using and he'll give me. but the OS and everything is a fresh install, up to date drivers and all. he said it could be that the manufacture of the cards are different cause one is ATI and the other is ASUS. if its cause of the 4x slot than its pretty much useless to put anything in it cause its just gonna drag it down?

I was using intel E220 dual core and 6gb ddr2 800mhz.

After i turned off crossfire the problem went away and it performed better than just the one card did alone. if i had 2 of the 3870 would it be better?

 

[clutchc]

As to the x16, x4 slots... Some articles you will read say that the x4 slot won't hurt if the 2nd card is of low enough bandwidth that it doesn't cause the 1st card to have to wait for a frame from the 2nd card. You may have a slightly different situation with 2 older slower cards in CF. I tried a x16, x4 board some time back with 2 x HD 6850s. Some games showed a very slight improvement over a single card, some actually had slightly lower FPS. Your mileage may vary. Run some benchmarks with 1 card and again with 2 cards and see for yourself.

Moving to a single HD 4870 would be somewhat of an improvement to the HD 3870/3850 you have now. And no m-s. The HD 4870 is a 150W (12.5A @ +12V) card. I would thiink it would be too much for a single 18A (+12V) rail, but if your other 2 cards are holding, the single 4870 should. What is the make/model of your PSU?

The other issue is the really weak 2.2GHZ dual core Pentium. It will bottleneck the HD 4870 to the point you won't be getting the most out of the card. You may be bottlenecking the 2 cards you have now, in fact. If you're financially stuck with what you have now, ask if you can borrow the HD 4870 for test. But don't be surprised if the PC shuts down when the card is stressed out. Oh, and the HD 4870 is a hotter running card, too.

Technically, 2 x HD 3870s would be faster than the combo you have now... but you might just overload the PSU then. And I doubt the dual core is allowing full benefit from the CF cards you have now, anyway.

 

[Blair Eudy Jr]

Ya I'm stuck with what I have to work with but i was thinking and it may be risky i got lots of power supplies, would it be too risky to connect 2 for the extra power if needed. I know how to do it just not sure if i should. you seem to know quite a bit i got a bit more powerful PSU it's only 550watt but the 12v rail is 36amps witch is alot better than the other but it doesnt seem to be able to power very much. i got it to power the board and a hard drive but when i put anymore to it it turns it on and then a few seconds after it showes the logo screen from startup it just shuts off. heat from the 4870 wont be any trouble I got fans and ventilation. and btw nice computer setup i really prefer AMD over intel but i dont any equivalent amd parts. and thx for all the help so far

 

[clutchc]

The PSU with the 36A rail would be better, but it doesn't sound dependable. Yes you can parallel 2 PSUs. You'll need something like this to turn them both on when you press the power button:
http://www.frozencpu.com/products/5637/

A lot of enthusiasts build systems with dual PSUs. There are some cases made specifically for a pair of PSUs, and they have the necessary adapters built in.