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i5 750 @ 4 GHz Any tips ?

Discussion in 'CPUs' started by Cesar67, 28 Mar 2010.

  1. Chapa

    Associate

    Joined: 26 Feb 2010

    Posts: 34

    What VTT voltage do you guys put in?

    1.10 fails stress test.
    Auto is ok.

    Help
     
  2. OpenToSuggestions

    Capodecina

    Joined: 5 Aug 2006

    Posts: 11,113

    Location: Derbyshire

    Friend has the P55-UD5 and I have the P55A-UD3R. Both very good boards and whichever is chosen won't dissapoint. The UD5 really is rammed with features.

    Any pro overclocker care to comment on Load Line Calibration? Is it better to use it or not use it?
    I am using it and prime95 failed after 3 hours at 1.29vcore and I am now priming with 1.3vcore at 4ghz (both with LLL on, I realise the vcore would be about 1.45v without).

    I am also hearing a lot on motherboard voltages. I have my ram at the rated voltage and I have set my own cpu voltage, however everything else is on auto. I have overclocked in the past but this is my first i5 overclock attempt.

    Any pointers much appreciated:)

    EDIT: I am most interested in QPI/VTT voltage, PCH Core voltage and CPU PLL voltage. I will leave the DRAM Termination voltagfe at auto as I don't intend to clock the ram past its rated 1600mhz.
     
    Last edited: 30 Mar 2010
  3. Cesar67

    Hitman

    Joined: 30 Dec 2008

    Posts: 660

    Location: SCOTLAND

    Although, I am far from an experienced over clocker, It works great for me.
     
  4. iMacMart

    Capodecina

    Joined: 8 Jun 2006

    Posts: 11,730

    Location: Hertfordshire

    UD5 it is then ;)

    Will go and have a read now! Offers from other retailers? I only buy from Ocuk?

    Thanks though
     
  5. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    Auto is bad, it may set it up as high as 1.35V - maximum absolute voltage for VTT acc. to Intel is 1.21V. Have a read through my post here - http://forums.overclockers.co.uk/showpost.php?p=16194325&postcount=571.

    I'd say let it be 1.21V and check if it fails 20 loops of IBT as I said earlier.

    I didn't mean to insult you in any way tweakinfreak, I think everyone has a right to search for the best offers that suit them. The only reason I said that earlier was because I noticed the RAM you speced earlier wasn't listed in OcUK but appeared with the exact name on the competition's site. I assumed you would get the rest of your rig from there too. In fact I bought half of my rig there simply because it worked out better for me.
     
    Last edited: 30 Mar 2010
  6. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex


    I recommend UD5 because it's excellently priced atm and besides having plenty of useful features allowing the board for more stable overclocks, it does provide symmetrical Crossfire which isn't supported by lower versions of this board afaik.

    I'm not a pro-overclocker either but from my own experience, I'd say LLC has a lot to do with a specific board and voltage spikes caused by the vdroop. You have to be aware that overvolting over a certain point with LLC enabled, you risk damaging your CPU. It's safer with it off but more stable with it on (reversed load and idle voltages). My board for instance has problems with both. With LLC off I get 0.6-0.7V under-shoots under load and with it enabled - 0.4V over-shoots. I can leave with that but I'm aware of voltage spikes that aren't recorded by CPU-Z and could possibly damage my chip.
     
  7. Mean Mr Mustard

    Hitman

    Joined: 3 Feb 2010

    Posts: 540

    I've got the UD5 board and a H50 cooler.

    VTT - 1.18v
    Core - 1.275v
    LLC - Enabled, Level 2

    I've got 4Ghz stable, 20 runs of IBT passed and max temp around 73C - a bit high for my liking but nothing else will heat it up like IBT.

    I've read up a bit about LLC and opinion is pretty much divided on it. Some say it's ok, some say it'll damage your CPU. I'm happy to leave it enabled until it's proven that it'll damage the CPU (I'm also aware it may cost me 160 quid to find out :p)
     
  8. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    Mr Mustard, what voltages do CPU-Z shows you under full load and in idle?
     
  9. Mean Mr Mustard

    Hitman

    Joined: 3 Feb 2010

    Posts: 540

    1.264 idle and goes up to 1.296 under full load.
     
  10. Chapa

    Associate

    Joined: 26 Feb 2010

    Posts: 34

    I have US3L motherboard and Zalman Extreme

    Stable now at 4 ghz
    Vcore 1.264
    VTT 1.15
    Ram 1.64

    Max temps 64 degrees. Really happy

    Load line calibration all disabled.

    VTT on auto was stable, but someone said it was dangerous. Then tried 1.10 and it failed.
     
  11. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    Chapa, did you read my post I pointed out earlier?

    Can you seriously turn off LLC and with these voltages:

    Vcore 1.264
    VTT 1.15
    Ram 1.64

    Achieve stable 20x200 overclock? :eek:

    I wanna cry and bin my chip asap.
     
  12. OpenToSuggestions

    Capodecina

    Joined: 5 Aug 2006

    Posts: 11,113

    Location: Derbyshire

    You sure LLL is off? VCore of 1.26v @ 4ghz seems far too low. I have never heard of an i5 750 hot 4ghz under 1.35-1.45volts without LLL.

    Thanks for the posts Chapa, Mr Krugga, Mean Mr Mustard, Tweakinfreak and Cesar67.
    I will get stable with LLL on, then I will try without and up the vcore. I will try the VTT voltage now at 1.20v.

    I notice that some people are saying that the intel recommendation for core temp is 72.7c, however in IBT my stock cpu with stock cooler was over that:eek:.

    Any comments on the PCH Core or CPU PLL voltage? Both are still on auto right now. Also are the CPU PPL, PCH Core, VTT and VCore related in any way?
     
    Last edited: 30 Mar 2010
  13. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    http://forums.overclockers.co.uk/showpost.php?p=16194325&postcount=571

    I'd say PCH and PLL left on auto or just above the stock till you meet some serious problems overclocking with core voltage tweaks. This won't probably happen by reaching 3.8GHz or so. PLL 1.89V and PCH 1.1V are safe afaik. They are related to PCI-E controller and NB connection iirc.

    Keep temps below 75-80*C and you should not encounter any problems :) It's mostly a safety margin for warmer ambient temps.

    EDIT

    It would be nice if you could provide some feedback on what voltage increases you needed for specific clocks. Eg. 3.5GHz for stock volts (1.2V), then 1.25V for 3.7GHz, etc.
     
    Last edited: 30 Mar 2010
  14. OpenToSuggestions

    Capodecina

    Joined: 5 Aug 2006

    Posts: 11,113

    Location: Derbyshire

    I passed IBT v2.4 with 1.3v and LLL enabled with VTT on auto. I set VTT to 1.21v and it failed IBT after 12 passes on maximum (which to me seems very very close to stable).
    Can I up the vcore to counteract this? Or does this mean I cannot have 4ghz unless I up the VTT again?

    EDIT: Good link btw.
     
    Last edited: 30 Mar 2010
  15. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    Don't worry mate, I'm just countering the same problem, 1.21V seems too low for stable overclocks over 3.8GHz with reasonably low v-cores. Yeah, try upping the v-core till 1.35V, report what you achieved. If it fails, go back to 1.3V and try 3.8GHz (20x190) with 1.21V on VTT.

    Yeah, there aren't many people who seem to be aware of potential dangers carried by uncore voltage of Lynnfield higher than 1.21V... It's the same with overvolting the memory controller over 1.65V.
     
    Last edited: 30 Mar 2010
  16. OpenToSuggestions

    Capodecina

    Joined: 5 Aug 2006

    Posts: 11,113

    Location: Derbyshire

    My Ram is only at 1.65v because G.Skill rate it at that.
    I only failed IBT after 12 passes with 1.21V VTT. Using 1.23v VTT it passes 20 IBT and did not fail at all. Tomorrow I intend to up the vcore and leave VTT at 1.21volts and see what I can get.

    Tbh I cannot give much of a overclock log as I went straight to 4ghz:p
    However, I had no idea about VTT, most guides say leave it on auto! I wonder what OCUK do in their pre-clocked bundles and systems.

    EDIT: I can say that VTT has an effect on cpu temps though. I will continue testing tomorrow after work.
    Please ignore my sig! I have an i5 750, Gigabyte UD3R, 4gb G.Skill 1600mhz and a beasty noctua cooler.
     
    Last edited: 30 Mar 2010
  17. OpenToSuggestions

    Capodecina

    Joined: 5 Aug 2006

    Posts: 11,113

    Location: Derbyshire

    Passed 20 IBT whilst prime95'ing overnight at 1.306 (the next setting over 1.3000) with VTT at 1.21volts :)
    LLC still on, will tackle that soon hopefully:)
     
  18. iMacMart

    Capodecina

    Joined: 8 Jun 2006

    Posts: 11,730

    Location: Hertfordshire

    Oh no problem mate, none taken, I brought it off MM but alas it's no good so trying to cancel the deal and get some more suitable RAM for my overclocks :)
     
  19. Chapa

    Associate

    Joined: 26 Feb 2010

    Posts: 34

    Sorry guys for my confusion, my VTT was always on lol

    My turbo thing is the one i have off.

    Stable Clock 4 ghz 200X20 vcore 1.264
    VTT 1.15 (1.10 was not stable and auto was)
    Ram OCZ 1.64 volts

    This has been stable overnight with prime95, temps at 64 degrees.

    Will try IBT this afternoon and report back.

    What settings i run IBT and how many loops?

    Thx
     
  20. Mr Krugga

    Sgarrista

    Joined: 16 Oct 2009

    Posts: 8,900

    Location: Essex

    I would consider this http://www.overclockers.co.uk/showproduct.php?prodid=MY-025-PA&groupid=701&catid=8&subcat=1517 and this http://www.overclockers.co.uk/showproduct.php?prodid=MY-042-GS&groupid=701&catid=8&subcat=1517 memory.

    You confused LLC with VTT again ;)

    Have you got power saving options (C-states, C1, EIST) turned off in BIOS)?

    IBT - 20 loops - Custom - 2560MB or more memory used (if you can, do 307 or maximum)