No question.
No question.
Sorry everyone. I’m just starting out with Overclocking. These questions might be quite old. Still, after searching the forum for three months, I haven’t found a clear answer. I hope you can assist me.
My setup:
Main: P5Q-Pro
RAM: 8GB DDR2 800Mhz
PSU: Masterwatt Cooler Master 650
I’m trying to overclock some Core 2 Duo CPUs so the PCSX2 can run properly. The software emphasizes core speed more than L2 Cache, which is why I need a CPU that can handle high overclocks. Since E7500-7600 models have more multipliers than E8600, they should be able to reach higher core speeds. Is that correct?
2/ Why do people usually prefer Q6600-6700 over Q9XXX?
3/ Should we not set the FSB higher than the DRAM? Is that right? My RAM is capped at 400 MHz, so shouldn’t I never raise the FSB above that?
With those older Core designs, the optimal method for overclocking is through the FSB. It's not about the multiplier much. The choice of using the Q6600 or Q6700 comes down to having a lower FSB, specifically 1066mhz here. This frequency is quad pumped, which means the base RAM speed becomes 266 times four (266 x 4 = 1066mhz). The Q9xx models feature an FSB of 1333mhz. Running at 333mhz with a quad pump setup keeps it within your DIMMS range (400mhz). You can typically adjust the FSB on your motherboard to switch between 266 and 333mhz, which will increase CPU clock speeds. This is the simplest approach. If you're using a GO version that boots directly onto the CPU, you might not need to adjust VCore to maintain the overclock. Instead, just change the FSB to 333mhz or 400mhz if your board supports it—though some boards have a FSB range between 333 and 400mhz, making it tricky to exceed 333mhz. With the Q9xx already offering a 1333mhz FSB, pushing the CPU further becomes challenging. On one of my older rigs, I swapped the FSB from 266 to 333mhz on a Q6600, and the clock speed jumped from 2.4 to 3ghz—very straightforward.
The E7500 features a multiplier of 11, E7600 offers 11.5, and E8600 provides 10. At 400FSB this results in frequencies of 4.4GHz, 4.6GHz, and 4.0GHz. Exceeding around 4.2GHz seems unlikely even with the highest safe voltage of 1.45v, as the additional multiplier offers limited benefit. It's worth noting that 4.2GHz is already achievable at 130w through your 65w dual-core chip, so strong cooling would be necessary for further overclocking.
Many people favored the Q6600 because it was affordable used when the Q9650 was priced around $40. You could also attempt to overclock the Q6600 in OEM systems like Dell, HP, or Lenovo by modifying the chip to 1333FSB. Only the more expensive X48 model officially supported 1600FSB, making a jump to the next official FSB unlikely for Q9xxx models.
Raising the FSB beyond RAM is only feasible with mobile (laptop) chipsets. Intel permits setting RAM frequency higher than FSB, though DDR2 generally performs well in overclocking. P45 has the lowest latency at 1600FSB, but you might need to adjust settings manually for optimal results.
In short, to achieve overclocking at 4Ghz or above, I must pick between two paths:
1/ Change DDR2 800Mhz to DDR2 1066Mhz, which allows FSB up to 533;
2/ Purchase CPUs with a multiplier of 10 or more: Core 2 Quad (Q6700), Core 2 Duo (E7300-7600 at 10x), E8600 (10x), E6700 (10x); Pentium Dual Core (Pentium E6300-E6800 at 10.5x–12.5x).
Regardless of the choice, I must ensure:
- Temperatures stay under 85°C
- Voltage remains below 1.45 for most models (except Q6700 and C2D E6700 which can reach up to 1.5V)
Is this correct?
Thank you all for your help. ^^
I've never encountered a quad that remained stable above 450, whereas dual options with 500+ are readily available. Opting for a higher multiplier helps reduce stress on the entire system, including the RAM.
What would be the best approach to cool a 65nm quad? A Q6700 is already operating at 230w at 3.8GHz, assuming a safe voltage of 1.55v, and pushing to 4.0GHz+ seems impractical for any 65nm chip in the long term. You have the appropriate board to achieve this, as it supports an 8-pin CPU power and 8-phase VRM, but a custom cooling loop would be necessary. Your board is compatible with the S771 platform.
The ideal quad choice would be a modified 45nm Xeon X5470 with a multiplier of 10.
I’d love to see such low temperatures—85°C is perfect—but I’m comfortable with 95°C in Linpack as long as stability is maintained. No software can reliably drive temperatures this high; if the system remains stable and avoids throttling in extreme cases, it’s safe to proceed.
Pentium dual-core chips generally have less robust dies even after cache optimization. Running one at 4.0GHz required 1.4875v, which is well beyond the advertised limit. These units are now affordable under $5 and are considered acceptable for performance. Overall performance was comparable to a 6MB-cache dual running at 400MHz slower.
I recently tested with Celeron 430 and Pentium E5500. Nowadays, just one core CPU seems insufficient even for running Windows 7. Even after trying to overclock the Celeron 430, it simply can't function properly. It appears this CPU is designed only for Windows Vista or earlier versions. As you mentioned before, I managed to overclock the E5500, but it still struggles. The CPU has a 14 MHz multiplier, yet I can't adjust its FSB beyond 40 (plus 200). Although the voltage remains within safe limits according to the manufacturer's guidelines, the temperature stays low—around 50°C—but the system frequently crashes with a blue screen. I'm unsure if my CPU is defective or if this is normal behavior for every Pentium Dual Core. Therefore, overclocking seems to be best suited for Core 2 Duo and Core 2 Quad processors.
The FSB has no connection to DRAM speed.
I previously had E7400 and Q9550 (Core 2 Quad) CPUs.
Regarding overclocking:
Motherboards from that time weren’t very reliable for that. Even if it functions initially, there’s a significant chance of damaging your motherboard.
I believe the most effective overclock would be replacing the Q9550 with a model at 2.83GHz (FSB-1333, 4 cores, L2 Cache 12MB).
Thank you. My aim is to reach an OC of 3.8ghz for smooth PCSX2 performance. The software only uses two cores and doesn't prioritize L2 Cache. That's why I'm experimenting with Pentium and Core 2 Duo.
I'll stick to this plan:
Pentium: E5700
C2D: E8500; E8600
Quad: Q6700 (10x multiplier)
I'll check the results soon. ^^
Pentium Dual Core not suitable for overclocking.
- Using E5500 (FSB 200; 14x multiplier), I cannot exceed FSB of 240 (3.36Ghz). The system will likely display a blue screen soon.
- With E5700 (FSB: 200; 15x multiplier), setting FSB to 240 (3.6Ghz) is not possible. The PC even fails to launch Windows 7.
Thus, achieving an OC around 20-30% remains unattainable. In short, Pentium Dual Core isn't recommended for overclocking. If we aim for OC, we must rely on C2D and Core Quad. Disappointing. --'