Overclocking a Kuma 7850BE

[Eureka]

So I'm kind new to CPU overclocking. I understand the basics of it, multipliers and FSB.

So running on stock voltage, I was able to achieve an overclock of 3200mhz. (16x200)
However, the computer was unstable, I am not sure if this was because I overclocked the ram from 4x200 to 5.33x200. I do believe it is the RAM though.

I set the RAM multiplier to 4x now.

I was able to get 3200mhz stable (13x250) with ram of 1000mhz (4x250).

How do I check stability? What programs do you guys use?

Also, what is the next course of action to take from here? Is it better to take my luck with FSB? Multiplier? Upgrade the voltage?

RAM is running at 1.8+.3 = 2.1v.
CPU is running at 1.3v

Sorry I am kinda new to this, so not sure whats the best option to take.

 

[Rifter]

i had a 7750BE that did not OC well so i would not expect much, why are you overclocking the RAM? is it 800 or 1066 RAM? the BE's have a unlocked multiplier just leave the ram at stock speeds and keep upping the CPU multiplier till its unstable then start to add voltage. Use Prime95 to test CPU stability and memtest for the RAM.

 

[formulav8]

Those with the amd 750 southbridge are getting decent 3.3ghz-3.5ghz ocs.

Other non-acc boards are getting 3.1-3.3ghz or so on average.

Besides those Kuma cpu's perform quite well. Especially with the very low $59 (7750) and $69(7850) prices.



Jason

 

[Eureka]

Well I figured I'd try to overclock everything on this system.

I'm using a Gigabyte MA790X-UD4P board (yes the newegg combo). I'll check out Prime95 and memtest, thanks!

And its 800mhz ram, I'm trying to get it to 1066, before I had (5.33x200mhz) and that was giving me issues, right now I have (4x250mhz) and its relatively OK.

EDIT:

Ran Prime95, crashes within 3 minutes. I got Core Temp up, the processor is idling at 52C and was at 79C when computer BSOD. I'm thinking I need a better cooler? (using stock)

EDIT2: I'm an idiot.. I had voltage at 1.6.. now it's at 1.3 and idling at 35C.

Also, what is better, a lower multiplier with higher FSB, or vice versa? Say:
3.2ghz:
16x200mhz, and ram is running at 800mhz
or
13x250mhz, and ram is running at 1000mhz

What are the benefits and downsides to each one?

 

[chubbyfatazn]

I'm using the same combo as you are, except that my board has the 790GX. I got mine to 3.3GHz with 1.4v.

Did you find the processor's max clock first? I would recommend doing that first before dealing with the RAM. Also, what cooler are you using?

 

[Eureka]

I'm using the stock cooler. What do you mean by max clock? As in FSB clock? Or overall speed?

Right now I'm holding relatively stable with 3.25ghz @ 1.4V. I haven't tried bumping it up any further, but I've been playing Crysis for the last 2 hours without any hiccups.

EDIT:
Also, core temp is being a bit funky. Its reading only one core temperature (CPU #0), and its reading VID as 1.3v. I assume VID is the core voltage? It does see both cores (2 cores, 2 threads).

In CPU-Z, it sees 1.45V (which is what I have it at).

Some kind of incompatibility with the motherboard/chipset? Or from running it on a 64-bit system?

 

[chubbyfatazn]

Originally posted by: cevilgenius
I'm using the stock cooler. What do you mean by max clock? As in FSB clock? Or overall speed?

Right now I'm holding relatively stable with 3.25ghz @ 1.4V. I haven't tried bumping it up any further, but I've been playing Crysis for the last 2 hours without any hiccups.

EDIT:
Also, core temp is being a bit funky. Its reading only one core temperature (CPU #0), and its reading VID as 1.3v. I assume VID is the core voltage? It does see both cores (2 cores, 2 threads).

In CPU-Z, it sees 1.45V (which is what I have it at).

Some kind of incompatibility with the motherboard/chipset? Or from running it on a 64-bit system?

If you mean to bump the voltage I would definitely recommend a better cooler. $20-$30 can get you a fairly decent aftermarket cooler if you don't want to spend a lot of dough on one.

By max clock I meant its maximum clock speed you can attain with it. When I overclock, I find that first and work my other settings around that number.

Last I checked VID is the chip's stock voltage.

 

[Eureka]

Ok, well right out of the box I could do 16x200 with Windows booting (3200mhz). However too much stress and it would crash. Setting the multiplier any higher would cause the machine to stop POSTing (and an annoying jumper reset task to be had). I'm also doing 13x250, which is 3250. This is as high as I can go so far to boot Windows, but running prime95 still crashes it.

Well, right now I'm upping voltages and running prime95, its crashing and I don't believe from heat (max temp I've seen so far is 65C). So would a better cooler do me any good in this situation?

Actually, I think running it at 16x200mhz is unstable, while doing 13x250 is at least working. Why is the lower mult/higher fsb running better than the high mult/lower fsb?

 

[Eureka]

Ok right now I just reached 3.3ghz!! And this is most likely my wall.

I have 255 FSB x 13mhz = 3315mhz
Which makes memory x4 = 1020mhz

Using CPU voltage 1.45V, NB at 1.3V, SB at 1.4V, and NB VID +.2V

Where to go next? This setting keeps prime95 happy for about 3-7 minutes depending on the weather and how happy it is.

 

[lopri]

Where do you have your CPU-NB (frequency, voltage), while you overclock?

 

[veri745]

Also, there's a good chance your RAM could be at fault since you're using DDR2-800. Try finding your max stable RAM freq (check the stickies for how), as well as your max CPU freq.

*edit* and you really want prime95 to be stable for 8-12 hours. also try OCCT. If I get OCCT stable for 1+ hours, prime95 is usually 24/7 stable.

 

[Eureka]

Originally posted by: lopri
Where do you have your CPU-NB (frequency, voltage), while you overclock?

Not sure about that, the voltage increase I've posted, but I'll have to check the exact voltages when I get home, at work now so I don't have the numbers on me.

Originally posted by: veri745
Also, there's a good chance your RAM could be at fault since you're using DDR2-800. Try finding your max stable RAM freq (check the stickies for how), as well as your max CPU freq.

*edit* and you really want prime95 to be stable for 8-12 hours. also try OCCT. If I get OCCT stable for 1+ hours, prime95 is usually 24/7 stable.

I'll have to look into OCCT.

I was thinking RAM, however I've also tried keeping the FSB at stock (ram x4 = 800), and just upping the multiplier. However I think I had less success doing it that way.

And the reviews on this RAM (Patriot Viper green 2gb sticks) usually report good overclocking results, at least up to 1000mhz.

 

[kamaaina]

I have not pushed the voltage as much but I seem to find some sort of a limit as well. I have it running at 3.2 Ghz with plain multiplier adjustment to 16x200Mhz. CPU Voltage increased to 1.4. It's running "stable". It ran for about 30 min on Prime torture and then was giving me a worker rounding error. No crash though. Runs BOINC research crunching for 24h without problems. FSX at max settings works a well. I am running Vista 64 SP2. Multiplier set to 17 did only boot halfway. Ran Easytune6 yesterday and autoclock set it to 16x 206.4, about 3.3 Ghz. Heat does not seem to be an issue yet (Artic Freezer Pro 64). Will play some more with it over the weekend. The motherboard is awesome. You can save different bios settings for future use etc. Awesome.

 

[kamaaina]

Originally posted by: formulav8
Those with the amd 750 southbridge are getting decent 3.3ghz-3.5ghz ocs.

Other non-acc boards are getting 3.1-3.3ghz or so on average.

Besides those Kuma cpu's perform quite well. Especially with the very low $59 (7750) and $69(7850) prices.



Jason

3.3 - 3.5 Ghz.? I have a 750 SB. Any ideas what settings that would be?
Thanks

 

[kamaaina]

Eureka, btw, Newegg still has the Freezer Cooler for $30 w/ free shipping: http://www.newegg.com/Product/...c%20freezer%20pro%2064
That thing is pretty good regarding price/value

 

[Gikaseixas]

Eureka get a better cooler. I bet you'll be able to bump the frequency up and keep it stable.

Stock cooler just won't do it.

 

[Eureka]

Well, I just ordered myself a Xigmatek HD-1283something (the 120mm) and I'll be picking it up today. I want to keep temperatures down/up the voltage. It comes out to $38 - $10 rebate and a free USB cable (ok not much of a logical combo but still).

Originally posted by: Gikaseixas
Eureka get a better cooler. I bet you'll be able to bump the frequency up and keep it stable.

Stock cooler just won't do it.

I thought cooling didn't have a direct affect on stablity, but rather total temperature/voltage. On stock cooler I've never had it go past 70C on load unless I bumped the voltage past 1.55v.

Either way, I'm going to try overclocking this a bit more, and then upgrade to a 940 once prices drop.

 

[kamaaina]

70C ??? I don't know what the rules are but I believe 70 is a temperature range that might be OK for graphic chips (gpu) but not for the CPU. My understanding is once you go >60 C you risk this thing dying or at least shorten life expectancy for good.

I had most success with stretching older CPU's when keeping idle temps under or around 40C and <50C under load. If it goes a few higher probably fine as well. However, since you are basically trying to run the CPU on it's limits, the cooler you keep it the higher the limits and better the stability. You can easily boot some higher clocked systems but you don't want the game to crash in the middle of the action. That's why the stock coolers are mostly useless once you go beyond a 10% performance increase.

 

[kamaaina]

I think there is still some room to grow. I have it at 3.4 ghz now, not stable though. Just crashed after 30 min. of regular windows activity (at 1.425V). Now at 17 x 200, CPU at 1.45V, RAM at 2.1V, NB, SB, and VID slightly raised. CPU cores are 35C idle, 43C when BOINC is running in the background (CPUID hardware monitor). Have not done prime yet as crashed anyway
I will post back if I get this stable.