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AMD 7750 Black Edition - Faulty?

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April 5, 2009 11:35:55 PM

I am currently running the PII 720 OC to 3.3GHZ on the ECS 780GM board & it is stable. I am switching the 720 to a new board (Biostar 790GX). I purchased a AMD 7750 BE to run in the ECS board but am having serious trouble overclocking. I can not get it to run stable past 2.9GHZ. I thought that this was supposed to be a good chip to OC? I have removed the tv tuner & added a 2nd 120MM fan to the computer. I'm running this on a 420w power supply. Any thoughts?
April 6, 2009 12:09:52 PM

what make of power supply and what southbound?

if it's not a corsair, seasonic/SilverPower, PCP&C or OCZ Fatal1ty then thats why it's unstable. And if it's not a SB750 then it won't oc as far as it can.
April 6, 2009 1:05:13 PM

The power supply is PCP&C (80 certified) & the SB is only 700. I plan to try the 7750 on the new Biostar 790Gx (750SB) & a new 550W power supply to see what's possible. I must say, I am a little let down after reading all of the reviews for this processor.
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April 8, 2009 7:12:02 AM

I'm have trouble running mine above 2.9 at the moment. I get some funky wavy lines then nothing if I increase past this. That's with the 790GX, which funnily enough made no difference over the 740G I tried before.

Going to reseat the heat sink again, I'm not too happy with the temperatures. Although what temperature is accurate I don't know since the BIOS, AMD OD, ASROCK OC all report different temperatures.

It should be pointed out not all processors are made equal, we could just have CPU's without a good overclocking threshold.
a b K Overclocking
April 8, 2009 8:21:50 PM

Are you using the stock cooler? Keep in mind that the stock cooler is the same one used on 65W Athlon X2 parts. It's really not meant to handle much more than the heat the 7750 outputs at its default clock speed. With artic silver and the default cooler I took my cousins 7750 to 3.0GHz on an ASRock 780GFullHD (which has the SB700). While I could go farther by increasing the vcore, I couldn't leave it there because of the really high temps. It also was unstable past 2.9 if the HT speed was at the default 1600 so it ended up at 1400.

Anyway first lower your HT speed to 1GHz. Some artic thermal silver will help a little with your temps. Also lower the north core voltage 1 step below it's default (it will be fine at that voltage with an HT speed of 1GHz) and that will help to prevent the heat from rising as fast. If you already have high temps at 2.9 then you're not going to get too much farther than 3.0GHz unless you get a better heatsink.
April 17, 2009 8:20:05 PM

sorry if this sounds dumb, but to get my 7750 to 3.0, i just raised the multiplier to 15. Easy 3.0 OC from the stock speed of 2.7..

is that what you did as well or did you mess with the fsb and the other multipliers (i think the other multipliers you would have to touch are the HT speed multi and the RAM divisor)

can someone ring in?
April 18, 2009 7:23:34 PM

Some do not OC well at all, like mine, it will run at 2.9Ghz with only +50mv(1.375v) all day long 24 hours prime 95 no problem, it then need +300mv(1.625v) to be stable at 3Gz, i hate my CPU. I love my video card, my 4830 will hit 800 :)  guess you cant have everything.

System specs:
Foxcon A7DA-S
7750 kuma, currently at 3GZ burning away at 1.625v, want it to die so i can get PH II
Sapphire 4830 at 800/900
AC 550RF PSU
2x2GB Corsair XMS2 DDR 800 Memory
Seagate 7200.12 500GB
Samsung IDE burner, 22X
Sony 32" LCD HDTV 1366x768
April 20, 2009 12:28:07 PM

Yes I have only attempted to up the multiplier. I rarely adjust the voltage due to the desired longevity of the chip.

It seems as though my system, no matter the board and/or processor, when I mess with the FSB, I blue screen rather quickly. I have never had a system remain stable after an increase of more than 200mhz on the FSB. I don't know what my problem is with that. So now I don't even attempt to play around with it.

I just ordered the PII 940 (!) and will retire the 7750 to a cheap web-surfing build. I purchased it as a temporary fix, I just anticipated higher gains with the 7750. I may have been too greedy in my expectations.
May 1, 2009 5:11:52 AM

Thats funny lol, i am also going to upgrade to a 940 or 955 :) 
May 1, 2009 7:53:07 AM

I have heard of people getting their multiplier above 15x, although not too much higher. I was wondering how high you have gotten yours... I just built it last weekend, so I only went to 15x (3.0 no problems at all). I have a massive heat sink though (Xigmatek 92 mm rifle, very highly recommend it!) so I doubt I will ever have any heat issues. I won`t be doing any voltage oc`ing either, I want this chip to last... it is more than I really need already.

my rig:
AMD 7750 BE
GIGABYTE GA-MA790X-UD4P
XFX GTS250
G-Skill 4 G (2x2)
Western Digital Caviar Black 500
CORSAIR CMPSU-550VX 550W

replacing:
XP 2700+
ASUS ... (forgot)
Nvidia 5500
(big improvement!!)
May 6, 2009 8:49:19 PM

That is about right you have to remember that 7750 is built off of the first gen 65n chips . So anything over 3.0 is just lucky without very good cooling.
February 20, 2011 6:24:21 PM

Well i thought i was having trouble until i read this thread apperently im doin that bad at all but i am having problems with the OC of my ram if you could offer any advise i would like that :D 

Foxconn A7DA-S
Athlon 7750BE OC at 3115 Mhz Voltage 1.32 14x223
Revven Sythe (modded with a 120mm fan strapped on the instead of the stock 90mm)
Antec 900 case
Sapphire 5750
F2-8500 G.Skill ram 4 gb (had problems OC that to 1066)
1Tb seagate 32mb cache
and input on the ram OC'ing would be help full



was thinking about upgrading Mobo ram and CPU to
MSI-fuzion mobo
AMD phenom 555BE
mushkin silverline 1333Mhz ram
February 20, 2011 6:25:29 PM

Plus i never get over 25C with OC at 3.1 Ghz
!