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Help..overclock E8400 on a GA-EP45-UD3P

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February 24, 2009 6:01:25 PM

Ok yet another noob overclocking help request. I think I have the basics down but I wanted to get some settings that would push my E8400 as far as it would go with standard intel cooling.

From what I have gathered so far I need to disable all the speedstep stuff. Got that ok.

I know how to increase the FSB speed and set the timings manually. Got that.

I know you have to set the PCI-E freq clock to 100mhz with PCI clock synch to 33.33mhz manually to keep the freq from getting too high when you up the FSB.

The tutorial I saw here as a sticky used the Asus Phoenix BIOS as an example instead of the Gigabyte Award BIOS which I have. They are similar in settings but different in many as well. Seems the Award has many more auto and turbo type settings from my old Asus board.

I don't get how to set the FSB/DRAM speed ratio on the board. I am running a 3.0GHz E8400 with Corsair XMS DDR2 mem rated at PC1066. From what I read for my memory the ratio should be 5:8.

Can anyone give me the settings for this BIOS to push it as far as it will go with stock cooling? I plan on getting a cooler later but my system is brand new.

Help with initial settings please?
February 24, 2009 6:06:05 PM

donfm said:
Ok yet another noob overclocking help request. I think I have the basics down but I wanted to get some settings that would push my E8400 as far as it would go with standard intel cooling.

From what I have gathered so far I need to disable all the speedstep stuff. Got that ok.

I know how to increase the FSB speed and set the timings manually. Got that.

I know you have to set the PCI-E freq clock to 100mhz with PCI clock synch to 33.33mhz manually to keep the freq from getting too high when you up the FSB.

The tutorial I saw here as a sticky used the Asus Phoenix BIOS as an example instead of the Gigabyte Award BIOS which I have. They are similar in settings but different in many as well. Seems the Award has many more auto and turbo type settings from my old Asus board.

I don't get how to set the FSB/DRAM speed ratio on the board. I am running a 3.0GHz E8400 with Corsair XMS DDR2 mem rated at PC1066. From what I read for my memory the ratio should be 5:8.

Can anyone give me the settings for this BIOS to push it as far as it will go with stock cooling? I plan on getting a cooler later but my system is brand new.

Help with initial settings please?


I apologize but there is another similar thread already posted with a similar setup to mine. But if anyone would like to walk me thru this anyway I would appreciate that very much. I am new to this BIOS and I really need a step by step kinda walk thru. Or a link to a tutorial using the Gigabyte Award BIOS
February 24, 2009 11:02:36 PM

Here are the BIOS settings I want to use for my first overclock. Could someone please tell me if I am doing this correctly?
GA-EP45-UD3P , E8400 , 4Gb DDR2 1066 Corsair XMS( rated at 2.1V) , 750W PSU,Sapphire HD4850 GPU

RGB: auto
Clock Ratio: 9X
CPU Freq: 3.0Ghz
CPU Host ****: enabled
CPU Host Frequency: 360Mhz
PCI Express Frequency: 100Mhz

DRAM CONTROL

Performance Enhancement: Standard
Extreme Memory Profile: auto
(G)MCH Frequency Latch: auto <--(do I need to manually set this and to what freq?
System Memory Multiplier: 2.66D<-- (not sure if I should be using A,B, C or D multiplier)
Memory Frequency 1066 960
CAS: 5
tRCD: 5
tRP: 5 <---------these are the rated settings for 533Mhz operation
tRAS: 15
tRC: 22

CPU VCore: 1.25V processor rated from .8v - 1.325v
CPU Terminate: auto
CPU Pll: auto
CPU Reference auto

DRAM Voltage: 2.1V
DRAM Termination: auto

MCH Core: auto
MCH Reference: auto
MCH/DRAM Reference: auto

All Speedstep features are disabled

Am I on the right track here. I have not applied these setting yet but I just wanted to do a mild overclock to see if I was on the right track before I burned anything up. If my calculations are correct this should give me about 3.24Ghz overclock.

I wish someone could explain the SPD multiplier setting and which A, B, C or D section I should be using. I don't get it.
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a b à CPUs
February 25, 2009 11:59:04 PM

Basics put simply:
Your OC will be [fsb] x [multi] = CPU speed. Adjust memory speeds to get close to your 1066 stock speed.

Your fsb is whatever you set it to and then the multiplier of an E8400 is 9(max, /w speed step it will be lower).

But...... just buck up and buy an aftermarket cooler if you plan to OC. An OC from 3.0 to 3.2 doesn't really get you that far.

It doesn't have to be pricey, this works great for me: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
a b à CPUs
a b K Overclocking
February 26, 2009 12:59:15 AM



Don, what your talking about is known as a FSB/Memory strap, Gigabyte calls it System Memory Multiplier. IF you set it to 2.0 your ram will be running at 1:1 with the FSB setting. Since your ram is duel channel ram (hence the 2X multi) if you set the FSB to 400, your ram will be running at 800 Mhz. This strap can be changed to run faster or slower depending on what you want the ram to run at, 400 FSB, strap 2.4 = 960 Mhz. and so on.

February 26, 2009 1:20:32 AM

RJR said:
Don, what your talking about is known as a FSB/Memory strap, Gigabyte calls it System Memory Multiplier. IF you set it to 2.0 your ram will be running at 1:1 with the FSB setting. Since your ram is duel channel ram (hence the 2X multi) if you set the FSB to 400, your ram will be running at 800 Mhz. This strap can be changed to run faster or slower depending on what you want the ram to run at, 400 FSB, strap 2.4 = 960 Mhz. and so on.


The straps in BIOS are divided into 4 sections....each section has a Letter after the numerical values. The letters correspond to different chipset buss speed values from what I can gather. I understand the memory multiplier but how do you know which section with which letter (A,B,C or D) to use with the multiplier. for instance how do you know to use strap FSB x2.4B in your example rather than FSB x 2.4D?

So far everyone I have asked just sort of tries them until they work without really knowing why they use the letter value they do.
February 26, 2009 1:27:11 AM

calinkula said:
Basics put simply:
Your OC will be [fsb] x [multi] = CPU speed. Adjust memory speeds to get close to your 1066 stock speed.

Your fsb is whatever you set it to and then the multiplier of an E8400 is 9(max, /w speed step it will be lower).

But...... just buck up and buy an aftermarket cooler if you plan to OC. An OC from 3.0 to 3.2 doesn't really get you that far.

It doesn't have to be pricey, this works great for me: http://www.newegg.com/Product/Product.aspx?Item=N82E168...



You are correct an overclock to 3.2Ghz won't get me too far. My purpose was to learn how to overclock gradually rather than burning something up. I can always go higher but once I fry my board I can't go lower.....:)  I am coming from an Asus BIOS board and the new Gigabyte mobo has many more options in BIOS that I need to learn first before I do anything drastic.

I understand the concept of FSB x Multiplier = CPU speed. I also understand you adjust your memory speed as close to your rated memory speed with the memory strap multiplier x FSB.

As you have suggested I decided to spring for a CPU cooler. All I have to do now is wait until one goes on sale at Newegg.... :lol: 
February 26, 2009 12:24:18 PM

I copied this information from the link you gave me. I still don't exactly get it.:




If you can hit the same Mhz with a lower strap you are doing better
A strap 266Mhz
B strap 333Mhz
C strap 200Mhz
D strap 400Mhz

Using a C strap to do DDR2 800Mhz will outperform the A,B or D strap doing 800Mhz with the same timings.

Each strap has it's own mutlipliers, all of them have the 2x multiplier.
For example:
Strap B has 2x, 2.4x and 3.2x
Strap D has only 2x and 2.66x

So if you set your fsb to 400Mhz
CPU multiplier x 9 gives you 9x400=3,600Mhz
D Strap multiplier x 2.66 gives you 2.66x400=1,064Mhz


Each strap above has a speed and a letter assigned to it.
My FSB runs natively at 333Mhz normally with my E8400 and my memory is DDR2 1066. My mobo effective FSB is 1600 mhz rated max.
So if I boost my FSB to say 400 mhz would I use the B strap(333mhz since my native buss is 333mhz) with a multiplier that would get me as close to 1066 as I can get....or the higher D strap with a similar multiplier(since my new speed FSB is 400 and strap D is 400mhz?

Where I am having the problem is understanding how the 4 speeds above relate to my FSB. Do you choose the speed closest to your native FSB speed? So for example anything 400Mhz and above would mean I use the 400mhz D strap and so forth. Then if I changed my FSB speed somewhere between 400 and 333 Mhz do I select the strap closest to that number and so forth?

I must be brain dead because this just isn't sinking in. Nobody tells you WHY you use it in the many threads I've read they just tell you to use the one that works the best which is not very scientific. There has to be some kind of rule here as to which one to use for which situation..... :D  If using the C strap will outperform all other settings as the text in red says..then why would you just not use the C strap all the time???
a b à CPUs
a b K Overclocking
February 26, 2009 2:05:32 PM

WELL, brain dead: NO Over analyzing this strap thing: YES

Most times the straps (A,B,C,D) will yield different ram variables, at least in the ASUS Bios it does. You may have two straps with the same outcome (maybe in Gigabyte's there are more). In that case you have two choices, you can run stability tests on the variables, then run a whole suit of synthetic and real world benchmarks to determine what one is more favorable (minute difference at best), or just pick the lower one. I've never taken the days it would take to analyze the difference but if you are willing, it would be an interesting post.

February 26, 2009 3:48:05 PM

RJR said:
WELL, brain dead: NO Over analyzing this strap thing: YES

Most times the straps (A,B,C,D) will yield different ram variables, at least in the ASUS Bios it does. You may have two straps with the same outcome (maybe in Gigabyte's there are more). In that case you have two choices, you can run stability tests on the variables, then run a whole suit of synthetic and real world benchmarks to determine what one is more favorable (minute difference at best), or just pick the lower one. I've never taken the days it would take to analyze the difference but if you are willing, it would be an interesting post.


Over analyzing??...Perhaps for the scope of this forum.

But I don't see where wanting to know how something works is a bad thing. Knowledge is power. And I choose to have the power to understand my board and its BIOS settings.

Perhaps the questions I ask are too difficult to explain to the lay person without an engineering degree (me). I have never been one to just take what people say when it comes to technical issues. You know what the say about "opinions". Everyone has one(the G-rated version). I need to know the WHY not just the HOW when I do something. I apologize if my questions are too technical for the scope of this forum.

Oh and by the way you still didn't answer my question. :pt1cable:  Perhaps there just no simple answer to the questions I ask and I am too technically challenged to understand the ones people have given. Thank you for your responses.
a b à CPUs
a b K Overclocking
February 26, 2009 4:15:48 PM

OK then, A,B,C,D is the MCH Strap, which means the internal timings of the MCH.

Lowering the MCH strap will give you the ability to lower the Static T
Read value giving you more memory bandwith (theoretically). :sarcastic: 


So, I did a little (quick) test:

FSB: 450
Mch strap: 400
Ram: 900 Mhz

Superpi 1M: 11.559 Seconds

FSB: 450
Mch strap: 333
Ram: 901 Mhz

Superpi 1M: 11.560 Seconds

You can take the explanation and results anyway you want. If you would like a more detailed explanation in a more technical manner maybe someone else can HELP YOU. :sleep: 
a b à CPUs
a b K Overclocking
February 26, 2009 11:49:54 PM



Well, had a little time tonight to play. So I decided to test 333 vs 400 strap and see if there was any bandwidth difference.

Sisoft Sandra

333 strap

Int: 8824 Mb's
Float: 8863 Mb's

400 strap

Int: 8774 Mb's
Float: 8784 Mb's

Well it looks like you do get a little benefit from the lower strap setting (stability may me compromised though), BUT as shown in the previous post (superpi scores) it really doesn't mean that much. It was fun to play with though.

a b à CPUs
a b K Overclocking
March 2, 2009 12:52:24 AM

I have the UD3R motherboard. I've searched, read, googled, and have yet to find anything that explains how the letters relate when you are setting your own cpu speed. I'm beginning to wonder if it matters which letter you use, but my system seems to run well so I'm not inclined right now to put a lot of time into experimenting with it.

The strange thing is that I have the same motherboard in a system that I ordered at work, it was just sourced about 2 months earlier. When I OC'd it I don't recall that it had the letters, I seem to remember just setting it to 2.00 and going with that.
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