Question Is Core 2 Duo E7400-7600 better than E8600 in overclocking?

[Lancelotsan]

Sorry everyone. I am the newbie in Overclocking. These questions may be very old. But after three months to search in the forum, I still can’t find the answer. So, I hope everyone can help me.

My spec:
Main: P5Q-Pro
RAM: 8GB DDR2 800Mhz
PSU: Masterwatt Cooler Master 650

1/ I need to overclock some Core 2 Duo CPUs to run PCSX2. That software more focus on core speed than L2 Cache. That is why I need a C2D CPU which can overclock as much as it can.

Because E7500-7600 have more multiplier than E8600. That mean these E7500-7600 can overclock to higher core speed than E8600. Is it right?

2/ Why everyone usually favor Q6600-6700 than Q9XXX?

3/ Someone tell me that we shouldn’t set FSB higher than DRAM. Is it right? My RAM can’t be overclock. So, its DRAM just 400. That mean I never should set FSB higher than 400???

Thank you, everyone.

 

[Roland Of Gilead]

Hmmm. Actually with those older Core architectures, the best way to OC is via the FSB. Not so much the multiplier.

The reason why people go for the Q6600/6700, is the have a lower FSB, in this case it's 1066mhz. The 1066 is quad pumped, meaning that the base speed of the ram is 266 x 4 (1066mhz).

The Q9xxx has an FSB of 1333mhz. This is from ram running at 333mhz, and again quad pumped. So if you have 400mhz ram, both the base frequencies are in range of your DIMMS (400mhz)

On your mobo, you should be able to change the FSB from 266 to 333mhz, which will boost your CPU clockspeed. This is the easiest way. If you have a GO version stepping on the CPU, then you may not even have to change vcore to keep the OC. Just change FSB to 333mhz, or 400mhz if your board supports it (some have a FSB whole between 333-400mhz, so it can be difficult to push beyond 333mhz

With the Q9xx already having a 1333mhz FSB, it's hard to push those CPU's further.

On one of my older systems I had a Q6600, and simply changed the FSB from 266 to 333mhz, and this changes the clock-speed from 2.4 to 3ghz. Easy peasy.

 

[BFG-9000]

E7500 has multiplier of 11, E7600 11.5, and E8600 10. At 400FSB that would give you 4.4GHz, 4.6GHz, 4.0GHz. It's pretty unlikely you'd be able to exceed ~4.2GHz anyway at the maximum safe voltage of 1.45v so the extra multiplier doesn't help much. I should point out that 4.2GHz is also already at 130w through your 65w dual-core chip so you'd better have some good cooling--anything that would support a mildly overclocked quad.

Everybody liked Q6600 because they were under $10 used when Q9650 was still $40. And you could even overclock the Q6600 in OEM machines such as Dell, HP or Lenovo just by padmodding the chip to 1333FSB. Only the expensive X48 officially supported 1600FSB so bumping up to the next official FSB was not going to happen with Q9xxx

It is impossible to set the FSB higher than RAM unless you are using a mobile (laptop) chipset. Intel does allow you to set the RAM higher than FSB. DDR2 actually overclocks pretty well, but P45 actually has the lowest latency right at 1600FSB. You may have to manually tinker with the Static tRead Value for lowest latency--on ASUS it's called Common Performance Level

 

[Lancelotsan]

Thank you. So, summary, to overclock to 4Ghz or higher, I have to choose between two options:

1/ replace DDR2 800Mhz with DDR2 1066Mhz, so the FSB limit to reach to 533.

2/ Buy these CPU with have 10 multiplier or higher:

Core 2 Quad: Q6700

Core 2 Duo: E7300-7600 ( 10x – 11.5x); E8600 ( 10x); E6700 ( 10x)

Pentium Dual Core: Pentium E6300-E6800 (10.5x – 12.5x)

But no matter what option I choose. I always have to be careful:

- The Temp always have to below 85.

- The voltage always below 1.45 for almost of these CPUs ( exclude Q6700 and C2D E6700, which the max voltage can reach to 1.5v).

Is it right?

Thank you for help, everyone. ^^

 

[BFG-9000]

I've never seen a quad that was stable much above 450, while it's easy to find duals that do 500+. It is far better to use a higher multiplier to minimize stress on the rest of the system including the RAM.

How would you cool a 65nm quad? A Q6700 is already at 230w by 3.8GHz assuming the maximum safe 1.55v, and 4.0GHz+ is unrealistic for any 65nm chip long-term. You do have the right board to push a quad as it has an 8-pin CPU power and 8-phase VRM, but would need a custom loop to cool that. Your board is on the S771 compatibility list so the correct quad to choose is a modded 45nm Xeon X5470, which has a multiplier of 10.

I would be delighted to have such low temperatures as 85c but am fine with 95c in Linpack so long as it is stable. No real software will push temperatures so high, so if it's still stable and under throttling temperature in a worst-case scenario then it's good to go.

The Pentium Dual-Cores tend to not have the greatest dies, even after disabling most of the cache. I had to use 1.4875v to get one to run at 4.0GHz. Yes, this is well over the published maximum but these are under $5 shipped now so can be considered expendable. General performance was about the same as a 6MB-cache dual running 400MHz slower.

 

[Lancelotsan]

Thank you, everyone. It help me so much.

Now I know what I have to do with my case.^^

 

[Lancelotsan]

I have just tested with Celeron 430 and Pentium E5500.

Today, One core CPU is too weak even to run Win 7. Even I try to OC Celeron 430, it total can't use for anything. One core CPU may be just be builted for Win Vista or older Windows.

As just as you said before. I OC E5500 and it is terrible. Although CPU have 14 Multiplier, I can't set its FSB more than 40 ( 200+40). Although the voltage still in safe limit ( follow the produce's info), the temp is low ( just 50), but the CPU soon get blue screen. I don't know if my CPU is bad, or it is the normal with every Pentium Dual Core.

So, really, OC is the job of Core 2 Duo and Core 2 Quad. ^^

 

[Endre]

Sorry everyone. I am the newbie in Overclocking. These questions may be very old. But after three months to search in the forum, I still can’t find the answer. So, I hope everyone can help me.

My spec:
Main: P5Q-Pro
RAM: 8GB DDR2 800Mhz
PSU: Masterwatt Cooler Master 650

1/ I need to overclock some Core 2 Duo CPUs to run PCSX2. That software more focus on core speed than L2 Cache. That is why I need a C2D CPU which can overclock as much as it can.

Because E7500-7600 have more multiplier than E8600. That mean these E7500-7600 can overclock to higher core speed than E8600. Is it right?

2/ Why everyone usually favor Q6600-6700 than Q9XXX?

3/ Someone tell me that we shouldn’t set FSB higher than DRAM. Is it right? My RAM can’t be overclock. So, its DRAM just 400. That mean I never should set FSB higher than 400???

Thank you, everyone.

The FSB has nothing to do with DRAM speed.

I used to have E7400 and Q9550 (Core 2 Quad) CPUs years ago.

About overclocking:
Motherboards from that era were’t very good at that. Even if it works in the beginning. There’s a high risk to fry up your motherboard.

I think that the best “overclock” you can do is an upgrade to Q9550 (2.83GHz, FSB-1333, 4-cores, L2 Cache 12MB).

 

[Lancelotsan]

The FSB has nothing to do with DRAM speed.

I used to have E7400 and Q9550 (Core 2 Quad) CPUs years ago.

About overclocking:
Motherboards from that era were’t very good at that. Even if it works in the beginning. There’s a high risk to fry up your motherboard.

I think that the best “overclock” you can do is an upgrade to Q9550 (2.83GHz, FSB-1333, 4-cores, L2 Cache 12MB).

thank you.

However, my goal is OC to 3.8ghz to run good PCSX2. That software just use two core, and almost don't care about L2 Cache.

That is why I am trying with Pentium and Core 2 Duo.

Follow that goal, my best choice may be is:
Pentium: E5700
C2D: E8500; E8600
Quad: Q6700 ( 10 multiplier)

I will test and report soon. ^^

 

[Lancelotsan]

Continue the report:

Pentium Dual Core not be creat for OC.
- With E5500 ( FSB 200; 14 multiplier). I can't set FSB higher than 240 ( 3.36Ghz). The PC will get blue screen soon.
- With E5700 ( FSB: 200; 15 multiplier), I can't even set FSB at 240 (3.6Ghz). The PC can't even open the Window 7.

So, they can't even reach to " OC around 20-30%" as someone said. Summary, Pentium Dual Core not be creat for OC. If we want to OC, we have to use C2D and Core Quad. So sad. --'

 

[Endre]

Continue the report:

Pentium Dual Core not be creat for OC.

• With E5500 ( FSB 200; 14 multiplier). I can't set FSB higher than 240 ( 3.36Ghz). The PC will get blue screen soon.
• With E5700 ( FSB: 200; 15 multiplier), I can't even set FSB at 240 (3.6Ghz). The PC can't even open the Window 7.

So, they can't even reach to " OC around 20-30%" as someone said. Summary, Pentium Dual Core not be creat for OC. If we want to OC, we have to use C2D and Core Quad. So sad. --'

If you can’t afford to buy a modern PC, then the Intel Q9550 CPU remains the best option for that motherboard.

 

[BFG-9000]

High FSB is actually quite important for performance on socket 775. As you have DDR2-800 I would strongly suggest just leaving it at 400 and only overclocking by adjusting the multiplier. Otherwise the FSB will bottleneck the DDR2.

With those Pentium Dual-Cores, I suggest going straight to 1.5v Vcore and trying multipliers 9, 9.5 and 10. After all, you already have them and they aren't worth anything, so why not see what they can do?

While a Core 2 Quad would certainly provide the best Windows performance for general-usage, even a heavily overclocked one drawing well over 200 watts would perhaps barely match a modern 15 watt Pentium Gold dual-core--that's what 10 years has given us. PCSX2 also runs on modern PCs but may prefer clockspeed over efficiency, and the Pentium Gold is only 2.3GHz.

 

[Sandywich999]

Continue the report:

Pentium Dual Core not be creat for OC.
- With E5500 ( FSB 200; 14 multiplier). I can't set FSB higher than 240 ( 3.36Ghz). The PC will get blue screen soon.
- With E5700 ( FSB: 200; 15 multiplier), I can't even set FSB at 240 (3.6Ghz). The PC can't even open the Window 7.

So, they can't even reach to " OC around 20-30%" as someone said. Summary, Pentium Dual Core not be creat for OC. If we want to OC, we have to use C2D and Core Quad. So sad. --'

I think you have a bad chip. I have both a Pentium E5700 and a core 2 duo E7400

With the E5700 I got 3.9Ghz once but that doesn't work anymore. But 3.75Ghz is stable and it benches 180cb+ in cinebench R15. So 25% OC without touching voltage

I'm using the core 2 duo in a PC now and it's at 3.5Ghz stable. Can't push it any higher but it gets the same score in cinebench. Mostly because of the extra 1Mb cache.

 

[DSzymborski]

Please don't necro nearly four-year-old threads without an *extremely* compelling reason.