X-bit labs

Another Gift to Overclockers: AMD Sempron 3100+ on E Core Revision (page 5)

Category: CPU

by Ilya Gavrichenkov

[ 04/04/2005 | 06:06 PM ]

Overclocking

As we have just seen, the performance of Sempron processors on the new Palermo core hasn’t changed that much. However, besides the SSE3 instructions support and enhanced memory controller, the new core should also boast higher frequency potential. At least the E core steeping for high-performance processors aka Venice can work at frequencies over 2.8GHz without any specific extra cooling (for more details see our article called AMD Athlon 64 3800+ CPU: E3 Processor Core aka Venice at the Door). This fact gives us hope that E revision of Palermo core will also show similar results.

So Sempron processors on E core revision can turn out an excellent choice for an overclocker. Selling at affordable price, these CPUs can theoretically show very good level of performance, if you manage to overclock them successfully and reach high working frequencies.

The overclocking statistics for Sempron cores based on CG and D core revisions indicates that these processors have been producing up to 2.5-2.6GHz stable working frequency so far. And in this case the performance grew up to the level of mainstream CPUs (for more details see our articles called AMD Sempron 2600+ for Socket 754: K8 Architecture Made More Affordable and AMD Sempron 3100+ Overclocking). Keeping in mind that E core revision should boast pretty good frequency potential, we expect that the budget system owners will be able to clock their platforms up to the level of high-performance one without much effort.

So, let’s finish our theoretical discussions and move on to some practical experiments. First of all we would like to point out that successful Sempron 3100+ overclocking requires the use of high-quality mainboard, which can work stably with high frequencies of the clock generator. The maximum clock frequency multiplier of the Sempron 3100+ processor is 9x and it can be adjusted only into a smaller value. So, if we are aiming at breaking the 2.6GHz barrier, we will have to increase the clock generator frequency beyond 288MHz. Far not all the mainboard allow that. Our recommendations about the mainboards for Sempron overclocking experiments remain the same: the only chipset that suits for that is NVIDIA nForce3, and as for the brand name, you should definitely go for the product from a well-known company, which has earned its reputation of the overclocking-friendly solutions maker. As for us, we stick with DFI LANPARTY UT nF3 250Gb mainboard for our overclocking experiments with Socket 754 processors, because this board is known to be one of the best overclocking-friendly products for this socket type. This mainboard allows increasing the clock generator frequency to 300MHz and up without any problems (see our article called AMD Sempron 2600+ for Socket 754: K8 Architecture Made More Affordable for more details about this mainboard).

So, our testbed for overclocking experiments was configured as follows:

• DFI LANPARTY UT nF3 250Gb (BIOS N32LD128.BIN) mainboard;
• AVC Z7U7414001 cooler;
• Corsair CMX1024-4400C25 memory (1024MB, DDR550 SDRAM, 2.5-4-4-8);
• PowerColor RADEON X800 XT (AGP 8x, 500MHz/500MHz) graphics card;
• Western Digital Raptor WD740GD (SATA150) HDD;
• Microsoft Windows XP SP2 OS.

We will start our overclocking experiments on Sempron 3100+ processor based on the new 90nm Palermo core with raising the clock generator frequency without raising the processor Vcore. This way we managed to increase the clock generator frequency up to 286MHz in no time at all. In other words, keeping in mind that the clock multiplier equaled 9x, we managed to increase the processor actual working frequency from the nominal 1,800MHz to 2,574MHz. I should say that this almost free 43% frequency increase above the nominal value is a great achievement so far.

However, this is far not all the new Sempron processor core is capable of. As we know, 90nm AMD cores are very sensitive to any changes of the processor core voltage, thus reaching much higher clock rates with higher Vcore. That is why we increased the processor Vcore by 13% above the nominal for our further experiments: up to 1.58V. In this case the clock generator frequency raised to 298MHz and the system was still working stably. Unfortunately, we failed to hit the beautiful value of 300MHz: the system would boot-up but would never go through the stability tests. However, as soon as we dropped the clock generator frequency to 298MHz, all problems vanished: all stability tests including Prime95 and S&M were completed successfully. The CPU temperature in this case didn’t exceed 55^oC.

So, with the processor Vcore increased by 13%, we managed to reach 2,682MHz clock rate, which is 49% above the nominal value.

Is it a lot or not? On the one hand, this frequency is definitely higher than the nominal frequency of any AMD processors, which allows us to expect the overclocked Sempron 3100+ on the new Palermo core to perform real well. However, on the other hand, we managed to overclock Athlon 64 processor on the Venice core (and this core is Palermo’s direct relative) to much better heights reaching 2.8GHz bar. Although we have already pointed out during our previous Socket 754 Sempron processors tests that these CPUs overclock a little worse than their counterparts from Athlon 64 product family. Maybe AMD uses lower quality dies for its budget solutions, especially since there is special equipment on Fab30 that supports APM (Automated Precision Manufacturing) technology, i.e. detects die features at early production stages.

Nevertheless, we should hardly complain about the obtained result. 2.68GHz core clock is higher than the nominal frequencies of the Athlon 64 processors and higher than the frequencies our previous Sempron processors on CG and D core revisions managed to achieve. So, now let’s find out how greatly the performance of the overclocked Sempron 3100+ on the new Palermo core improved compared with the results we have just obtained for the CPU working at its nominal frequencies.