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Help overclocking new i5 system

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AMDGuy

Member
Joined
Apr 10, 2001
So I'm coming from a 4 year old AMD system to this new i5 system I've built, and whoa are things different. I need some help with overclocking this rig.

I'm not looking for the all out fastest settings I can use, but something good for 24/7 OC.

I'm also not sure about turning on or off the power saving features that allow CPU clock and voltage throttling. I believe the motherboard has some of these features as well as Windows 7 itself.

The components I used are:

i5 750 CPU
Gigabyte P55 UD3R mainboard
Megahalems CPU Cooler with 2 x 120mm fans in push pull config
OCZ Platinum DDR 1333 memory (2 x 2GB sticks)
MSI Radeon 4670 Graphics
Corsair 650TX PSU
6 x SATA HDD (2 x Raid1, 2 x Raid 1, 2 x Raid0)

OS is Windows 7 Ultimate 64-bit

I've tried to find some type of guide, but so far I've had no luck.

The Bios has a MIT settings area for overclocking, but there are so many settings I'm not sure what does what.

I'm unfamiliar with:

QPI Clock Ratio
QPI Link Speed
Uncore Clock Ratio
Uncore Frequency

I understand that the CPU Clock Ratio and BCLK Frequency determine the CPU speed (20 x 133 = 2.66Ghz default speed of the i5 750).

I understand that the System Memory Multiplier (SPD) times the BLCK Frequency determines the memory speed (10 x 133 = 1333 default speed of the RAM).

I'm unfamiliar with:
CPU Clock Drive
PCI Express Clock Drive
CPU Clock Skew

Below is a screen shot of the MIT section of the BIOS where OC settings are made...this is not mine, this is from another website that did a review of the mainboard.

76.jpg
 
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gwar2288

Member
Joined
Oct 6, 2009
I have the same Board, so here is what you need to do :p

First, Update the BIOS to the latest Revision.

Next, set the BClock to 200 and the Multi to 20. Set the Memory Multiplier to the lowest setting, even if it underclocks the ram for now.
In Advanced CPU features, turn off C1E, EIST, Turbo Boost and C6 State.
Leave the voltages at Auto for now.

Boot :p With any luck, you will boot into windows just fine and then use CPUz to check your Voltages and Realtemp to monitor your temps. Then it's just a matter of finding the lowest bootable voltage, then upping it by 1 to see if it runs stable. Just remember to set the Voltages manually as Normal and then as a + offset for the Dynamic vCore, otherwise when you find your stable OC voltage and turn C1E and EIST back on, the voltages wont drop as they should.

No idea what kind of cooling you have though. If it's the stock fan, ignore everything I have just said and leave it on Stock with Turboboost enabled. If you have a good Fan, try the above and report your temps under LINX or P95.
 
OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
I have the same Board, so here is what you need to do :p

First, Update the BIOS to the latest Revision.

Next, set the BClock to 200 and the Multi to 20. Set the Memory Multiplier to the lowest setting, even if it underclocks the ram for now.
In Advanced CPU features, turn off C1E, EIST, Turbo Boost and C6 State.
Leave the voltages at Auto for now.

Boot :p With any luck, you will boot into windows just fine and then use CPUz to check your Voltages and Realtemp to monitor your temps. Then it's just a matter of finding the lowest bootable voltage, then upping it by 1 to see if it runs stable. Just remember to set the Voltages manually as Normal and then as a + offset for the Dynamic vCore, otherwise when you find your stable OC voltage and turn C1E and EIST back on, the voltages wont drop as they should.

No idea what kind of cooling you have though. If it's the stock fan, ignore everything I have just said and leave it on Stock with Turboboost enabled. If you have a good Fan, try the above and report your temps under LINX or P95.

I think I have the latest updates on bios and all that. F6? If memory serves, but I'll double check.

Cooling is a Megahalems with a huge 50x120mm Panaflow pushing and a 25x120mm pulling across it. I think cooling should be good.

I followed most of what you said, up until the part about setting the voltage as "normal" then upping by 1??
 

Raoul Thorley

New Member
Joined
Dec 16, 2009
Location
Australia
This thread is of great interest to me as I am almost certainly going to be picking up a P55 Gigabyte motherboard next week as part of a new system build for myself, so any help that people can supply would be awesome.
 
OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
Ok looking over some more setting last night I think I'm ready to start overclocking this machine.

My main questions still revolve around how to have the power saving features enabled with the over clock?

Ideally I'd like the machine to run at 3.8Ghz when needed, and throttle back when not needed.

Is that possible?

In the guides I've found online the first thing they do is disable all the power saving functionality like EIST and C1e.

I did a video encode test last night and the max cpu temp shown by CoreTemp was 44C. The system seemed to overclock itself to 2.8Ghz automatically when the encoding started.

At idle the system shows 1.2Ghz and runs at 27C.
 
OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
I found this article that should be of help to many going down this path.

http://www.xbitlabs.com/articles/mainboards/display/asus-p7p55d-deluxe.html

I will start some testing and once I find the sweet spot for my setup I'll post the results and how I achieved them.

Also, here are some explanations I found from user Meridian on another forum:

BCKCLK is the equivalent of the old-fashioned bus speed. UNCLK (uncore) and QPI run as ratios to it.
Uncore is the clock for the memory controller - what used to be the northbridge (but not the memory itself, which is a separate control).
QPI is the chipset (what used to be the southbridge) controller.
Thus, as you raise BCKCLK the other two will go up, and so will the RAM speed.

Please don't ask me about the voltage controls, because it will take me a while to remember which is which. By and large though, you can stay with just Vcore (the CPU) QPI PLL (QPI of course) and DRAM voltages for the early parts of your experiments. Later you can play with CPU PLL and CPU VTT!

The CPU also has a mutiplier, such that BCKCLK x mult = CPU speed. Mine is currently 196 x 21 = 4116MHz for instance.


Some rules:


1) Try to stress each bus in turn, so you know the limits. Start with RAM, then go through Uncore and QPI, and finish with BCKCLK.

2) Generally Uncore data speed should be at least twice memory, and QPI should be twice Uncore - some say x2 +1. So if RAM is 1600, Uncore should be 3200 and QPI 6400 or higher.

3) With i7, the max you can get Uncore is about 3500, and the max you can get QPI is about 7500, but I don't know for i5. You should aim to be as close to these figures as you can get without exceeding them - or whatever limits you discover.

4) The max you will get BCKCLK is probably about 205-210.


With that in mind, raise BCKCLK a little. Note the values of Uncore and QPI, and remember what I said in the rules. Test. Rinse and repeat. If it falls over, lower the RAM divider first. If that fails, look to the other speeds and lower each uin turn until you've fixed it. Last resort is raising voltages.
 
OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
Ok...UPDATE:

I've set the system to 180 bclk and 20x multiplier. I've set the SPD to 6.0 for a memory speed of 1080Mhz and left the default memory voltage at 1.50Vdimm for my OCZ Platinum sticks and set the timings to 8-8-8-22 and 1T.

I've set the Vcore to 1.25V (shows at 1.248 in CPUZ) and the Vtt to 1.15 both well within maximum range of 1.55 for Vcore and 1.21Vtt according to Intel's i5 Spec sheet here:

http://download.intel.com/design/processor/datashts/322164.pdf

Refer to section 7 for voltage tables.

The above settings gave me 3780Mhz on the CPU at full tilt. After 8 hours of Prime95 CoreTemp showed a max Temp of 59C, well below the 90C spec'd as max. I've set my alarms at 80C to be safe.

Some peculiarities:

1. With stock settings the Vcore and multiplier change according to CPU load. I've seen the multiplier go from 9.0X all the way to 24X. The Vcore would also fluctuate from less than 1V to 1.24V give or take a tenth. I presume these are functions of the Gigabyte P55 UD3R mainboard.

2. After enabling BLCK control, and leaving every other BIOS setting as default, the multiplier and Vcore no longer changed with load, but remained at a constant 21X. I found this odd, but maybe the board senses you're over clocking and disables the dynamic voltage and multiplier??

3. Once I had a decent idea of what the board was doing, I switched EIST from "Auto" which was the default to "Enabled". Now the multiplier changes from 9.0X to 21X depending on load. The Vcore will only drop to around 1.23V at idle, NOT below 1V as before.

4. With BIOS version F2 if I enabled C3/C6/C7 State I got a blue screen right as Windows 7 finished loading. I've not tried this with the NEW BIOS version F4, but will do so this evening.

I believe this processor has A LOT left in it. The Megahalems CPU cooler is doing a phenomenal job of keeping things cool with 2x120mm fans on it in a push pull config.
 
OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
Another UPDATE:

I tried to go a bit further tonight, but it's taking a bit of Vcore increase to get past 3.8Ghz.

My current settings are:

BCLCK 191
Vcore 1.32500
Vtt 1.15
Memory is still at 8-8-8-22 with the Vdimm set to Auto (1.50V) and the SPD is 6 for a mem freq of 1146Mhz.
Uncore is set to Auto.

EIST is enabled and C1E is enabled, but C3/C6/C7 causes a BSOD when booting to Windows 7 64-bit so it is set to the default of Auto.

I've got 4 threads of Prime95 running and the multiplier is jumping to 21X for a total speed of 4011Mhz.

Prime95 has been running for about an hour with no errors and CoreTemp is showing temps of 68,67,64,67.

I'm sure I can go further if I wanted to but I think I may call it quits at this point. I have a HD video clip I use to test performance since that's what I mainly do with my system and going from 3.8Ghz which didn't require any voltage increases to 4.01Ghz which requires a 0.075Vcore increase only shortened my test clip encode time by 15 seconds. The clip is 3 minutes long.

Here is a break down of encode times. This is going from AVCHD to DVD MPEG2 using Sony Vegas 9.0c 64-bit:

STOCK SPEED 2.66Ghz - 4:20
3.8Ghz - 3:15
4.01Ghz 3:01

So, at this increased speed (and Vcore) I'm only saving about 5 minutes per hour of encoding. I'm not sure it's worth the wear and tear on the chip.

Opinions?

At idle the multiplier drops to 9X for a speed of 1719Mhz, but Vcore only drops to 1.312 at idle. I haven't found a BIOS setting to allow the Vcore to drop down to 1.0V or lower like it did at the stock settings.
 
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OP
AMDGuy

AMDGuy

Member
Joined
Apr 10, 2001
Well, I think I've found the combination I'm going to use for a while.

Since this is a brand new system, and I typically like my systems to last 4 years before my next real upgrade I decided to back the Vcore down and run the chip at 3.8Ghz. I made this decision because my video encoding wasn't any faster at 4.01Ghz. I ran the same 02:40 AVCHD clip through Vegas9 64-bit encoded to DVD NTSC 3 times at both 3.8Ghz and 4.01Ghz and the encode time was always between 03:15 and 03:01. A mere 14 second increase in speed (about 5 minutes over an hour of video encode) wasn't worth the extra voltage required.

After the system is a couple of years old, I may bump it up to it's maximum and run it until it dies. That's what I did with my last system, and by the time I had bumped the system to it's fastest speed, with a bump in Vcore to achieve it, the system was out dated anyway so if it blew up I wasn't too upset. That system lasted an additional two years before giving up the ghost.

So without further ado, for those following along here is where I ended up:

Vcore 1.275000 which the main board automatically bumps to 1.28000 under full load. At idle with EIST enabled the multiplier drops to 9x for a freq of 1.6Ghz and the Vcore drops to 1.264.

BCLK = 181
Default Multiplier is 20x
Intel Turbo is turned on which bumps the mult to 21x under full load for a 3.8Ghz cpu speed.
QPI/Vtt voltage is 1.15V
QPI Ratio is Auto

Vdimm is set to auto which is 1.50V
Memory mode is Turbo
SPD = 6 for a memory speed of 1086 @ 7-7-7-16 1T

EIST = Enabled
C1E = Enabled
Thermal Alarm is set to 80C
Everything else is auto if memory serves.

The above combination ran 4 threads of Prime95 in blend mode over night. Three of the cores went 15 hours with no issues. One core failed after 8 hours. I guess one is weaker than the rest but 8 hours is good enough for me.

I've got a Megahalems CPU Cooler with 2 x 120mm fans in push pull. I even turned them down to their lowest speeds for this final test and the max temps were 65, 65, 63, 65. I can probably get rid of one of the fans to make the system even quieter.

I'm happy to help if anyone else has questions. It's a little daunting at first when you see all these new settings, but once you understand them and test them individually to find the limits it's pretty simple really.