Aces High Bulletin Board
General Forums => Hardware and Software => Topic started by: katanaso on February 15, 2010, 11:00:19 PM
-
Hey guys,
I'm OC'ing my E8400 to 4050MHz right now on a EA-EP45-UD3P Motherboard, but it's failing Prime95 at various times. I'm running with 8GB of Mushkin RAM as well, at 1080Mhz. I can post the voltages of everything, as well as my hardware setup, if there's any interest or response here.
If any of you are OCing an E8400 or E8500 to 4GHz or so, could you post your settings for the Processor and the Northbridge? I'd like to get this stable for a 24 hour benchmark of Prime95.
Thanks,
mir
-
I'm no OC expert, but I'd say your pushing it a step too far.
-
Considering the fastest 2GB DDR2 module Mushkin makes is DDR2-1066 at 5CL, I cannot see how you are clocking it at over 1Ghz, unless you are adding an enormous amount of wait states (CAS) to it. Even then, the signal cycle times are going to be too short for the RAM to setup before writes.
Is that the actual clock rate, or the "times 2" clock rate for the RAM?
I am running my DDR2-1200 RAM at an actual clock rate of 571Mhz, which has the same CAS as yours.
What after-market cooler are you running on the CPU?
-
Sorry, I should write better when it's technical.
The FSB was 450, and the RAM is running at a 6/5 ratio, so it's equivalent to 1080 (540MHz x2). It's the DDR2-1066 5CL RAM you're talking about, Skuzzy.
For CPU Cooling, I'm using a Xigmatek HDT-S1284 Enhanced Edition.
I dropped the FSB to 445 last night, upped the VCore one more step to 3.2xxxx(I can't recall immediately while at work), and was able to run Prime95 for 8 hours on the small test. The core temps are around 37 and 38 at idle, and got to the high 50's under 99% load. That was monitoring using Everest.
This is my first time really trying to OC a processor like this since the batch of Celeron 300A's came out in 1998 that would go to 450, so it's fun, but at the same time frustrating when I deal with the BSoDs and reboots...
-
I never up the VC of the CPU, as it shortens the life of the CPU and I run the RAM at whatever the recommended voltage is from the manufacturer.
Right now, I am at 571Mhz on the RAM and have the CPU at 3.6Ghz. Very stable.
-
I understand and agree about the negative aspect of it.
I was also running at 3.6Ghz without changing a thing, and the RAM was running over it's rated 533Mhz with the recommended 2.1v as well. And it was stable, running very cool.
It's more of a fun thing, since it's my home PC. I wouldn't dare think of playing with any of my servers like this where our organization depends on them, and I'd smack my staff if they were screwing around on any of our Windows boxes. :)
-
I've run an E8400 at 3.8 but it's happier (forgive the technical term) at 3.6. I run an E8500 at 4.0 with no problems. Memory at 1066.
-
Every time I try to OC, I get system crashes, the only time it does not crash if it is a very minor OC, so just does not seem worth it for me :cry
-
I had my E6750 OC'd from 2.66 to a shade over 3.5 Ghz just for fun once but I backed it back to 3.2 Ghz for daily use.
It seems to me that all the Intel CPU's OC by about 20% pretty easily. After that it gets tougher.
-
Hey guys,
I'm OC'ing my E8400 to 4050MHz right now on a EA-EP45-UD3P Motherboard, but it's failing Prime95 at various times. I'm running with 8GB of Mushkin RAM as well, at 1080Mhz. I can post the voltages of everything, as well as my hardware setup, if there's any interest or response here.
If any of you are OCing an E8400 or E8500 to 4GHz or so, could you post your settings for the Processor and the Northbridge? I'd like to get this stable for a 24 hour benchmark of Prime95.
Thanks,
mir
I can get mine up to 3.9 with a crappy cpu fan from bestbuy. but have it down to 3.6 since it more than run ah at full settings. would be interesting to see your voltages.
semp
-
Thanks for the replies. Here's what I'm working with now, which has been stable through some short Prime95 runs as well as Everest Stability Tests:
4050MHz
FSB 450
Multi 9
RAM at 540MHz
Vcore - 1.33125
CPU PLL - 1.57
CPU Termination - 1.26
CPU Reference - 0.785
DRAM Voltage 2.12
Running at 5-5-5 15 settings on the Mushkin RAM (can look at those if you'd like)
MCH Core - 1.28
MCH/DRAM Reference - 0.81
MCH Reference - 0.76
ICH I/O - 1.50
ICH Core - 1.20
Temps at idle:
CPU -35
Core1 - 40
Core2 - 38
Temps at 100% load:
CPU - 48
Core1 - 58
Core2 -58
Motherboard Temp stays around 46 at idle or load.
-
I'd be surprised if you can't run the memory at 800.
-
800 x 2? For 1600MHz? I don't think it will do it. I'll poke around on the net to see if people have done it with my model of RAM and relaxed timings.
Right now it's 540 x 2, so it's running at 1080MHz.
When I had the processor running at 3825MHz (425 FSB x 9), the RAM was running stable at 565 (1130MHz), but I didn't push it past that.
-
Why run the RAM faster than the CPU? You aren't gaining anything in doing so. If it was me I'd try lowering the RAM clock to sync it with the CPU and see if I couldn't tighten the timings to actually get a performance increase.
-
Sorry Mir, misread it. :D
-
Perhaps you should try what BaldEagl's saying and reduce your memory speed to achieve a 1:1 ratio between your memory and FSB. In my opinion, unless you increase to 2:1 ratio, you won't see any improvement except in synthetic benchmark programs. Either your memory is failing that your OC'd settings or your "North Bridge" is failing at the OC'd memory setting. Perhaps it's due also to your higher mobo temps of 44C. In my opinion, running below 100F would be ideal.
I run an E6400 2.13GHz OC'd to 3.03GHz
PC6400 underclocked from 400MHz to 380MHz (4 CL) (Dual Channel configuration to saturate FSB)
FSB is at 380MHz (effectively 1520MHz and up from 1066MHz)
-
Interesting concept, Kermit, and I read that having one faster than the other (FSB or Memory) can create a bottleneck.
It would be easy enough to drop the memory down to 1:1, allowing me to reduce the Northbridge voltages.
I wonder about a 533 FSB with 7.5 multiplier, then a 1:1 ratio as well.
The system is stable now, but yeah, it's warm.
-
You guys are forgetting about the bus masters in your computer, such as the video card and hard drives. The FSB has a direct impact on the transfer performance to/from RAM.
It does translate into real world performance gains. In my class in the videographers test, my computer is the fastest, even though there are thjose that have their CPU's clocked higher. The videographers test is a real world rendering test, not a synthetic benchmark.
-
Interesting concept, Kermit, and I read that having one faster than the other (FSB or Memory) can create a bottleneck.
It would be easy enough to drop the memory down to 1:1, allowing me to reduce the Northbridge voltages.
I wonder about a 533 FSB with 7.5 multiplier, then a 1:1 ratio as well.
The system is stable now, but yeah, it's warm.
Generally, to achive the same outcome, if you lower the multi with a higher FSB you'll create more heat than running a higher multi with a lower FSB. I can't see any reason to ever drop the multiplyer. If you're going to do that just drop the FSB instead and the vcore with it and eliminate heat.
-
Generally, to achive the same outcome, if you lower the multi with a higher FSB you'll create more heat than running a higher multi with a lower FSB. I can't see any reason to ever drop the multiplyer. If you're going to do that just drop the FSB instead and the vcore with it and eliminate heat.
Thanks. I'm reading about it as I can to see the pros and cons, and if it's even worth it.
I'm having to run my NB a little higher than standard as is, but that's only since I went to 4 sticks of RAM. When I had 2 sticks, voltages were default for the NB.
Is the 1:1 ratio for CPU/RAM a non-issue on motherboards that allow various ratios like the one I'm using, where I can get 1066 (533x2) and above by picking a specific ratio as needed?
-
Is the 1:1 ratio for CPU/RAM a non-issue on motherboards that allow various ratios like the one I'm using, where I can get 1066 (533x2) and above by picking a specific ratio as needed?
No, the issue is in syncing the clock speeds so that the RAM and CPU are at the same frequecies and both are exchanging data on the same clock cycles. Besides that overclocking the RAM beyond it's manufacturer specs and what's actually needed can destabilize the RAM resulting in an unstable OC.
If you could sync the RAM to the CPU at a lower clock speed it would be more stable. Then you could try taking the timings from 5-5-5-15 to 4-4-4-12 or something similar and actually speed the RAM up by lowering latencies. That would still leave the CPU and RAM on the same clock cycles but speed the data handling internally for the RAM so that it might be able to respond to a CPU data request in one instead of two clock cycles for instance.
-
If you could sync the RAM to the CPU at a lower clock speed it would be more stable. Then you could try taking the timings from 5-5-5-15 to 4-4-4-12 or something similar and actually speed the RAM up by lowering latencies. That would still leave the CPU and RAM on the same clock cycles but speed the data handling internally for the RAM so that it might be able to respond to a CPU data request in one instead of two clock cycles for instance.
Interesting.
If I could do that, with my current settings, it would be running the RAM at 900MHz. (450x2).
So, it would be 900MHz 4-4-4-12 or the current 1080MHz 5-5-5-15.
I wonder what the difference would be, giving up speed for a decrease in latency.
I'm not sure the memory could do it though.
-
I'm assuming not all MBs will let you change memory latencies? I can't seem to find it in the bios for my Gigabyte GA-M74GM-S2 rev 2.0. Only options I can find are Memory Clock and DDR2 Voltage.
-
Interesting.
If I could do that, with my current settings, it would be running the RAM at 900MHz. (450x2).
So, it would be 900MHz 4-4-4-12 or the current 1080MHz 5-5-5-15.
I wonder what the difference would be, giving up speed for a decrease in latency.
I'm not sure the memory could do it though.
You're not actually giving up speed. As it stands your RAM is running a faster clock cycle than the CPU and has to wait for the CPU on each data exchange effectively slowing it to the CPU's clock speed.
Just as with OCing the CPU reduce latencies one at a time and one step as a time and test for stability after each change. Don't just jump to 4-4-4-12.
I'm assuming not all MBs will let you change memory latencies? I can't seem to find it in the bios for my Gigabyte GA-M74GM-S2 rev 2.0. Only options I can find are Memory Clock and DDR2 Voltage.
Not sure. I can change mine. I've got an eVGA 780i motherboard. I don't remember offhand where it's located in the BIOS though.
I know that my Kingston HyperX DDR2 800 RAM defaults to 5-5-5-15 timings anytime you add a new stick even though the spec is 4-4-4-12. Kingston does this to assure compatability with a wide range of motherboards so, to get to spec, you have to manually set the timings and voltages. That being the case I'd guess that theres a place to re-set timings somewhere in your BIOS.
-
You're not actually giving up speed. As it stands your RAM is running a faster clock cycle than the CPU and has to wait for the CPU on each data exchange effectively slowing it to the CPU's clock speed.
Just as with OCing the CPU reduce latencies one at a time and one step as a time and test for stability after each change. Don't just jump to 4-4-4-12.
Gotcha.
What are the drawbacks from the RAM running faster than the CPU? (540 vs 450). More latency, due to the timings of 5-5-5-15, but anything else?
I lost my internet access yesterday, so I didn't see your post until today, else I would've played with the memory settings last night.
Thanks again.
-
May I suggest a review of the block diagram in this Intel PDF (http://www.intel.com/Assets/PDF/prodbrief/P965-prodbrief.pdf) file.
It is pertinent to all Intel CPU's prior to the i7 family, regardless of the Intel motherboard chipset. I'll point out the memory bus speed is between the memory controller and the RAM. The clock rate between the memory controller and the CPU is the external clock rate of the CPU.
Only reason I am bringing this up is due to some misinformation in this thread. Regardless of the FSB or CPU clock rates, the CPU always has to wait on a memory read on any cache miss. The CPU does not have to wait on writes as those are buffered in the memory controller which actually does the RAM writes for the CPU.
-
Thanks, Skuzzy. That makes it plain to see. I appreciate the diagram!
Is there an explanation as to why it's nearly 50% faster from MCH to RAM than MCH to CPU?
-
That will be dependent on the memory controller in the chipset and the CPU being used. The clock between the memory controller and the CPU is the external CPU clock.
The FSB clock is between the memory controller and the system RAM.
In early chipsets there was only one clock source and various multipliers and dividers were used to generate the FSB and CPU/MCH clocks.
With the Core Duo release the chipsets implemented completely independent clock sources for the RAM and CPU.
The ratio you see between the FSB and CPU clocks is for the memory controller so it can properly sync the two buses.
-
Gotcha. Thanks for the explanation there. :)
For resuming some tweaking, I was researching various boards, and read a bunch about tightening specific memory settings. I went over the the Mushkin Forums and found some good info there, and I changed some settings that lowered the latency by over 10ns, as well as increasing the read and write throughput several percent to around 9500 MB/Sec or so.
The FSB is 450 (9 multiplier for 4050MHz) and RAM is still 5-5-5-15 at 1080MHz (540x2). I had some attempts at 4-4-4-12 at 800MHz, but it wouldn't POST. Searching various sites suggested it's harder to work with 4 sticks of RAM than with just 2, but I wasn't going to open the system last night. Interestingly enough, I could overclock the RAM up to 5-5-5-15 at 1200MHz and boot into Windows, run programs, and work. However, it wasn't as fast as when I was able to modify the specific settings of tRRD, tWTR, tWR, tRFC, tRTP, and Static tRead at 1080MHz.
The system has been stable, and it passed some stress tests (Memtest86 and Intel Burn Test), and it is noticeably faster.
I stayed up too late fiddling with things, so I can't post the tweaks now, but I will tonight, as well as make sure it's running stable.
This is definitely an interesting and fun learning experience. :)
-
With the e8400 and Corsairs 800 Mhz RAM I linked and synched like the gurus suggest on the eVGA forums which required setting the memory voltage to factory specs and lowering the timing (from 5-5-5-18-2 to 4-4-4-12-1). Once thats all done it looks like the memory will under-perform at 667 but in fact with the RAM operating at 800 (1600 FSB manual entry) the CPU is operating at a stable 3.6 Ghz (3.599). The way it was explained to me is that Intel wants the market so even if they run out of 8400 processors they will take the under-achieving 8600s and label them as 8400s. Im not sure if thats true but every 8400 I have seen can easily do 3.6 and on air they dont even approach getting 'hot.'
Everest Home Edition reports my memory latency is zero (0) which cannot be right.