Hi, welcome to my guide for LGA775 overclocking! I felt like writing this guide because LGA775 can still be a capable platform, plus overclocking is fun. I also see a fair amount of misinformation about LGA775 and overclocking (e.g. They aren't unlocked so can't be overclocked.) So I just felt like putting a guide out there for those interested in doing it, or for those who just want to learn a thing or two. Let's start off with some basic terminology that you'll use when overclocking, some of this may be specific to LGA775. CPU Voltage (Vcore): This is the voltage delivered to the CPU.
Also note processor graphics overclocking ratio is multiplied by half of base clock. STEP 3: Run Stress Tests. 3.1 - Determine if stable Determine if the overclocked system is reliable by running one or more stress tests to confirm system stability. NOTE: The Intel Extreme Tuning Utility contains several helpful stress tests and benchmarks.
Generally when overclocking you increase the voltage to gain clock speed headroom. Typical stock voltage for LGA775 CPUs is between 1.15v and 1.325v. Generally a lower stock voltage means for a better chip. CPU FSB Voltage: When pushing for higher overclocks you may need to increase the FSB voltage. Most chipsets can handle around 1.3-1.4v max. DRAM Voltage: This is the voltage to the DRAM, sometimes you'll have to increase this is overclocking pushes your motherboard out of the DRAM spec. However in most cases you can just set it to the set DDR2 standard for your memory kit (Generally between 1.8 and 2.1v).
NB Voltage: Voltage to the north bridge, may need to be increased when pushing for bigger overclocks. Generally safe up to around 1.4v SB Voltage: Voltage to the south bridge, may need to be increased when pushing for bigger overclocks. Generally safe up to around 1.4v CPU ratio: This is the clock ratio set by Intel.
Typically ranging between 6 and 10 on most Intel CPUs. All but the extreme edition CPUs have what we call a 'locked' ratio, which means it can't be changed. Because of this there's a big misconception that I see quite often on the forum that LGA775 CPUs can't be overclocked. The clock speed is calculated by ratio.bus speed/frequency. 10 x 333 = 3330MHz) Bus speed: The bus speed is 1/4th of the FSB speed.
So common FSB speeds on LGA775 are 800, 1066 and 1333MHz. This means that each CPU would have a bus of 200, 266 and 333mhz respectively.
When we increase our bus speed we are increasing the effective clock speed of a CPU, as we're increasing the amount the ratio is multiplied. Bus speed also comes into RAM clocks, but we'll get to that later. FSB speed: The front side bus is the bus that controls the memory communications between the cache, when overclocking the FSB speed is increased. A pre-defined FSB is given to each CPU, for example a Core2Quad Q6600 has a FSB of 1066 (leading to a 266mhz bus speed).
The FSB requires memory at least twice the speed of the bus speed (1:4 from FSB). So a CPU with a 800MHz FSB can only operate at above DDR2 400MHz.
And a CPU with an FSB speed of 1333 must have at least DDR2 667 MHz. CPU Stepping: CPU stepping can be referred to the 'revision' of a CPU. Generally later steppings are capable of better things. For example on 65nm Q6600s the G0 stepping was a much better overclocker than the earlier B3 revision of the stepping. And on 45nm we had a similar with between C0 and E0 (E0 being better). Motherboard Chipset: A bit like today where we have H81, B85, H97 and Z97 we had chipsets.
Each chipset is aimed at a certain price points and this leads to some being better than others. Good LGA775 chipsets are as follows: 975X, P35, X38, 680i SLI., P43, P45 and X48.680i SLI is known to struggle with Core2Quads due to some chipset errata. Some basic maths. I'll use 2 CPUs as an example. I'll choose two popular ones, the Q6600 Core2Quad and the E8400 Core2Duo. Both CPUs had a CPU ratio of 9x. However one runs at 2.4GHz and one runs at 3GHz, why?
Well the E8400 has a higher FSB speed. (1066MHz vs 1333MHz). This means the bus speed for the two CPUs is different (remember, ratio. bus clock speed). So the 2400MHz for the Q6600 is calculated with 9.266MHz and the 3000MHz for the E8400 is calculated by 9.333MHz. Because of this the memory frequency will rise also, as the lowest memory speed is 1/2th the FSB or 2x the bus speed. So if we change our FSB to 1600MHz the memory (if previously running at DDR2 667) will now clock up to 800MHz.
We can combat this by either raising the voltage and loosening the timings, or by changing the divider, this means we choose say, DDR2 533MHz but as the bus speed is higher the effective frequency will be higher. This can lead to some strange frequencies.
If you're using a nvidia chipset like 680i or 790i you can keep memory speed unlinked to the CPU bus speed. This is helpful as it means you can generally keep a very consistent memory speed.
Motherboard chipsets and how they compare. So, identify the base speed and ratio for your CPU. A good tool to do this is, or you can just use your BIOS. Now set a target clock speed for your processor.
A fairly achievable clock on almost any CPU ( except a lot of the lower clocked 800mhz fsb cpus like pentiums/celerons, I'd target 2.8) would be 3.3GHz. So head into your BIOS, familiarize yourself with the settings and find the ones I've mentioned in the rest of this guide. Now when you find FSB speed or Bus speed (I find AMI BIOS list bus, and Phoenix FSB).
And set it to what you've calculated for your CPU. (frequency = bus.ratio).
Now also add 50mV to your CPU (0.050v). Reboot into Windows, run some benchmarks/stress tests and see if it's stable. If you're happy and want to push more, you can do the calculations to achieve higher clock speeds. If you're running into instability, try increasing voltage for some of the things I've mentioned above. You should also make sure your RAM is not running miles higher than it should be.
![Overclock processor software Overclock processor software](/uploads/1/2/5/6/125659343/106358634.jpg)
When aiming for high clocks it's generally beneficial to get faster RAM. If you're running DDR2-667 and are chasing a 500MHz+ FSB, you'll find you're running about 250MHz out of spec at minimum. This is because of the FSB:DRAM ratios possible with the chipset.
Again nVidia chipsets are generally more flexible with unlinked ratios. 1:1 FSB:DRAM ratio: When overclocking on this platform a lot of people aim to get a 1:1 FSB/DRAM ratio, this means that the CPU doesn't have to 'wait' on the RAM when communicating to the bus. This results in extra performance but isn't always achievable and isn't a massive gap either. This generally works best with low timings for speedy CPU/DRAM data exchange. To achieve this you'd set a DRAM ratio equal to your FSB.
So if you had a FSB of 500, you'd choose DDR2-1000MHz (500MHz effective). Recommended voltages. Any reason you listed max safe voltage for C2Q 45nm 1.35V? Max safe voltage is 1.45V. By the way, especially for this platform, I would first do small fft's in prime95 just to rule out the memory/and whatever again goes along with it and quickly getting an idea if the vcore was enough. Once that's stable, run blend and tweak the VTT/Dram voltage perhaps/NB. There are a few more voltages though like CPU GTL, DRAM GTL, Northbridge as well, on gigabyte boards its called reference, CPU GTL should be 0.67 of your VTT.
Gigabyte boards were scaling this automatically like it should be set. Include the 1:1 cheat and explain why faster RAM can be needed to achieve higher clocks, you explained this already with the FSB. FSB is quad pumped by the way, so a FSB of 333MHz is 1333MHz (can be seen in GPU-z fsb vs rated fsb). 1.40-1.45V for the FSB/NB/SB is quite a lot.
I needed like 1.2-1.3V for the NB/SB for 447MHz/900MHz. Any reason you listed max safe voltage for C2Q 45nm 1.35V? Max safe voltage is 1.45V.
By the way, especially for this platform, I would first do small fft's in prime95 just to rule out the memory/and whatever again goes along with it and quickly getting an idea if the vcore was enough. Once that's stable, run blend and tweak the VTT/Dram voltage perhaps/NB. There are a few more voltages though like CPU GTL, DRAM GTL, Northbridge as well, on gigabyte boards its called reference, CPU GTL should be 0.67 of your VTT. Gigabyte boards were scaling this automatically like it should be set. Include the 1:1 cheat and explain why faster RAM can be needed to achieve higher clocks, you explained this already with the FSB.
FSB is quad pumped by the way, so a FSB of 333MHz is 1333MHz (can be seen in GPU-z fsb vs rated fsb). 1.40-1.45V for the FSB/NB/SB is quite a lot. I needed like 1.2-1.3V for the NB/SB for 447MHz/900MHz I'm working on it, I think I mentioned that the FSB/bus was 1:4, but the DRAM min speed is 1/2 the FSB.
I said max recommended voltages, ideal for 24/7 use. From my experience the quads can get pretty toasty pretty quick. I'm working on it, I think I mentioned that the FSB/bus was 1:4, but the DRAM min speed is 1/2 the FSB. I said max recommended voltages, ideal for 24/7 use. From my experience the quads can get pretty toasty pretty quick Trying to remember, at 333MHz in a 1:1 ratio RAM would end up to be 667MHz so your requirement that RAM has to be twice at the FSB speed is correct (333.2=667mhz) or just half at the rated FSB on CPU-z (667/1333mhz = 1/2). 'Bus speed is 1/4th of the FSB', I assume you meant the bus speed in the bios is 1/4th of the speed thats quad pumped.
Tbh leave this out, honestly you're not a lot with this quad pump theory, as long as you know that your ram speed should be twice as fast as the FSB speed in the bios that should do it. If I OC the FSB by 67MHz (from 333MHz); 400MHz FSB with 800MHz RAM would be 1:1 a FSB:DRAM ratio - If I decide to get rid of my DDR2 800MHz stick and get a 1600MHz DDR3 stick and lets say my CPU can do it easily; 400MHz FSB with 1600MHz RAM would be in a 1:2 FSB:DRAM ratio. Side note: It was advised to lock the PCIe bus to 100.00MHz and the PCI/ to 33MHz or 33.33MHz can't remember it exactly anymore My experience with core2's is quite different they weren't running hot at all under a NH-D14. I can remember my Q9550 at 3.8GHz with 1.36V, idle 53° and full load after hours apparently 55°. I couldn't do 4GHz at all, so I just went extreme nuts and bumped every voltage out there except SB/GTL's, at 1.45Vcore wasn't even breaking 65° and still not stable A friends E7600 I think it was, had a stock clock of 3.06GHz and a multiplier of 11 afaik, got that thing in less than a minute at 3.8GHz. A higher multiplier was awesome, lower FSB clock which has a lot more headroom with slow ram was just epic. He had a NH-D14 as well, wasn't even breaking 45°.
Heres a video of a guy that shows his temps at 4GHz with a Q9550 & nh-d14; youtube.com/watch?v=le5VCSL6trk Sandy bridge was a different story for me, 4.7GHz and 1.37V gave me like 80° so I just upgraded my nh-d14 to a H100. Found my Q9550 at 3.8GHz using less power than my 2600K, but isn't a surprise when SB pulls a GHz higher clock Btw nice OC, just seen it, that's just a 2500K.
Trying to remember, at 333MHz in a 1:1 ratio RAM would end up to be 667MHz so your requirement that RAM has to be twice at the FSB speed is correct (333.2=667mhz) or just half at the rated FSB on CPU-z (667/1333mhz = 1/2). 'Bus speed is 1/4th of the FSB', I assume you meant the bus speed in the bios is 1/4th of the speed thats quad pumped. Tbh leave this out, honestly you're not a lot with this quad pump theory, as long as you know that your ram speed should be twice as fast as the FSB speed in the bios that should do it.
If I OC the FSB by 67MHz (from 333MHz); 400MHz FSB with 800MHz RAM would be 1:1 a FSB:DRAM ratio - If I decide to get rid of my DDR2 800MHz stick and get a 1600MHz DDR3 stick and lets say my CPU can do it easily; 400MHz FSB with 1600MHz RAM would be in a 1:2 FSB:DRAM ratio. Side note: It was advised to lock the PCIe bus to 100.00MHz and the PCI/ to 33MHz or 33.33MHz can't remember it exactly anymore My experience with core2's is quite different they weren't running hot at all under a NH-D14. I can remember my Q9550 at 3.8GHz with 1.36V, idle 53° and full load after hours apparently 55°.
I couldn't do 4GHz at all, so I just went extreme nuts and bumped every voltage out there except SB/GTL's, at 1.45Vcore wasn't even breaking 65° and still not stable A friends E7600 I think it was, had a stock clock of 3.06GHz and a multiplier of 11 afaik, got that thing in less than a minute at 3.8GHz. A higher multiplier was awesome, lower FSB clock which has a lot more headroom with slow ram was just epic. He had a NH-D14 as well, wasn't even breaking 45°. Heres a video of a guy that shows his temps at 4GHz with a Q9550 & nh-d14; youtube.com/watch?v=le5VCSL6trk Sandy bridge was a different story for me, 4.7GHz and 1.37V gave me like 80° so I just upgraded my nh-d14 to a H100.
Found my Q9550 at 3.8GHz using less power than my 2600K, but isn't a surprise when SB pulls a GHz higher clock Btw nice OC, just seen it, that's just a 2500K I added some stuff about fsb:dram ratios in post. Yea high multi chips were good, but I got my X5450 for £23.
I've been trying to overclock my laptop, an Acer Aspire e-15 SKU es1-511-C0DV. I know for a fact that this version of laptop is very unknown and uncommon. And it also kinda sucks. So, that beside the point, I was wondering if any of you out there with the same or similar laptops know how to overclock the processor in it, which is the intel celeron mentioned in the title. If any one of you have before, can you please tell me how to do it, for example what clock generator to use in setfsb or a BIOS flash for it and what speeds it operated the best at?
Thank you in advance for the people reading this.:P. Unless you have a high end custom laptop, laptops are not designed to OC, they all have limited bios that prevent this. Basically as a laptop has a limited space for all components, it's cooling capacity is limited, unlike a desktop, so overheating would be a major issue. That's what I thought.
Although the fan on my laptop barely turns on even when the cooling method is checked as 'active'. The temperatures stay around 30 degrees C at idle and around 30-35 degrees C under full load, like playing a game. So overheating isn't really that big of a deal for me. And that's why I asked if anyone knew of a bios flash for this model of laptop so I can change that limited clock speed.