Please Help with Overclocking e2140

[nomagic]

Hello Everyone,

Here is the spec:
Pentium Dual-Core E2140
Asus P5K SE motherboard
Asus 8600GT OC
A-Data 2048MB * 2
No-name-brand 350W PSU

I can't get the bus speed over 370MHz (or x8 = 2960Mhz core speed). The computer will not boot at all when >370MHz bus speed is set in bios. However, I heard that nearly all P35 boards can do well over 400MHz, and E2140 can be overclocked to 3.2 GHz easily. After looking over my spec, I now believe that if I get a quality PSU, maybe I can push the bus speed higher. However, I am not too certain. So can someone with more experience please help me out ? Would a better PSU help in this case? Or maybe PSU is not the problem?

 

[Mondoman]

The e2xxx core certainly seems to be able to handle 3GHz plus, but the FSB may be the practical limit on the e2140. Remember, 333MHz FSB is Intel's fastest currently shipping FSB; that's why some suggest going with the e2160 or e2180, whose higher multipliers allow 3GHz+ without having to exceed 333MHz FSB.

However, your PSU certainly seems unsuited to the task of an OC'd e2140 + modern highish-power graphics card.

 

[VirtualLarry]

Some E2xxx have FSB walls as low as 350-ish, so I hear. I was thankful that both of my E2140s would do 400FSB, but not all of them will.

 

[BonzaiDuck]

At VCORE of 1.346V at idle, the E2140 is capable of going to host-frequency = 333 Mhz and 2.67 Ghz w FSB = 1,333. This is a good match for DDR2-667 stix at their tightest latency settings.

If you look at the thread of E2140 and E2160 results by members, it shows the voltages (off the top of my head) in the 1.40+V range.

I've concluded that all of these E21x0 processors were built at the same specification and same error and failure expectancy, then their multipliers were locked at the end of the manufacturing process to differentiate three models.

In other words, the E2140 and E2180 both run at 2.67 Ghz at exactly the same VCORE with speeds of 8 x333 and 10 x 266 respectively. Keep in mind that I'm testing them in identical el-cheapo mATX motherboards and low-end nVidia chipsets, but I can only speculate that what others are showing in their results suggests higher voltage requirements.

Also, I must say that I'd be very uncomfortable with your power-supply. If it's a generic knock-out, there's no guarantee that it provides the full wattage of the rating. There's also no guarantee that the rails are stable under heavy, sustained load. I once had an ALLIED BCE-500 (as I recall the model name), for which the 12V rail fell from 11.8V at idle to something like 11.3V under load. It was frustrating my efforts to over-clock. I replaced it with a 520W OCZ PowerStream -- steady as a rock -- and the frustrations disappeared.

Even for a low-end processor and motherboard, try and get a decent PSU. See what the extreme wattage demands might be given your specific equipment choices -- use the Extreme Outervision PSU calculator (Lite) at their web-site. Usually, the estimates from that link are considered to be upwardly biassed under usage-assumptions that are unrealistic. But pushing the wattage on your processor will change the power demand on the PSU, and you can limit your calculation to the processor to see how it might change.

ANTEC Earthwatts is a good choice for the money.

 

[nomagic]

Thanks for the replies!

I replaced my no-brand PSU with a Seasonic S12II 380W. After some testing, I found that the no-brand PSU was indeed crippling my OC. Now I am able to get the bus speed up to 390Mhz. (3120Mhz core speed)

Then I replaced my stock heatsink with a tri-heat-pipe one, now the core temperature running orthos is about 53 degree Celsius according to Core Temp. The core temperature was approaching 70 degree Celsius with the stock one, but now the temperature is well within the safe range.

I really want 400Mhz bus speed, but the computer will not post (no beep, just led lights and fans) at that bus speed, so I set the CPU multi to 6 instead of 8, and made sure the speed and timing were below the spec. (DDR800,5-5-5-18) However, I still cannot get 400Mhz bus speed. No matter what the CPU voltage was.

I wonder whether or not I have hit the FSB limit of my ASUS P5K-SE. Or, is there something else that I missed?

 

[Replay]

"I still cannot get 400Mhz bus speed. No matter what the CPU voltage was. "

You can also try bumping up the voltage to the chipset bridges by one step to see if that helps.

Did the 6x multi allow you to reach a higher fsb? If not, you are hitting an fsb wall, which is most likely to be a cpu limit. Unless your ram has trouble at those speeds.

Usually best to test the limits of the memory, and the fsb, and then the cpu chip, one by one. Then you know where you stand.

Many 2140's will not reach your 100% overclock target. I have a chip which does 390x8 3120 at stock, and goes no further than 391, even with lots of extra voltage. It smacks hard into an fsb wall at 391 fsb. That is when a higher multiplier would have been handy. The high multiplier chip is more likely to respond to extra voltage, eventually limited by heat, before the fsb is too high.