Memory Characterization and Validation
The most critical aspect of overclocking your CPU is to determine just how far you can overclock you memory (and your board in general). Once we know exactly what our memory can do, it is no longer part of the variables. If you do not do this, you can never quite be sure what is limiting what and spend a lot of time changing random things and spinning in circles. With this board design the MCH (Memory Controller Hub) also becomes overclocked as FSB speeds increase and this actually tends to limit overclocking the entire system as well. There will be a more in-depth discussion in the extreme overclocking section. Regardless of the level of overclocking desired, all should go through the following steps and just quit when you are at your comfort level. First, a few words about what is normally limits the overclock on these boards.
Memory and MCH Heat Issues.
If you intend to do serious overclocking start the process now to get a fan on the MCH. Screw it on, hot melt glue, tye wraps, whatever. You must cool the MCH for reliable FSB's over 333. If you cpu has a multiplier of 9 or more its not quite as much an issue but you may find the super duper fast memory you bought was a waste of money. More on that later. During the next set of tests we need to employ the highly sensitve thermal probe located on the end of your hand. You have 10 of them so if one gets damaged its of no concern, to me :p. Each time you increment the FSB and establish a new "highest" FSB let memtest run for a few minutes and take your thermal probe (finger) and place it on a memory stick, either directly on a chip or if with heatspreaders place it in the middle of the spreader about 1/2 way down. If you can count to ten without removing your finger due to heat. you are good, if you hae to let go at 5 you are very warm and it could use some more air, how is up to you. If you cant make it to 3, you are killing your ram. You need to back off and get some air on it. We are still at stock voltage and extreme overclocking requires raising the memory voltage which produces a LOT more heat than we are creating now. So this is a serious problem if you are already running hot. Do the same thing for the MCH heatsink. It is the heatpipe/heatsink about in the middle of the board. It will probably be much hotter than a memory stick, dont damage your probe. Same deal, I think you will quickly find a fan is needed as we ramp up the FSB. Deal with it if you intend to OC. See the Hardware tweaks section for tips on putting a fan on the MCH. Repeatedly check the temp of these parts as you establish new FSB "records". The first and best thing you can do is tear off that ridiculous "bling" thin sheetmetal cover on the MCH so air can get to the fins. Flatten it back out and superglue it to your case for a "super sized" case badge, or not.
Memory/MCH Testing Strategy
Basic strategy, we will reduce the CPU multiplier to under clock the CPU and increase the Memory Mulitplier (for higher memory speeds) and raise the CPU Host Frequency (FSB) speed while we test the memory until we get errors. All of these settings are under the M.I.T. sub-menu in the BIOS. The first runs should be done at the manufactures recommended voltages. Take notes but it is probably not necessary to use the full listing I presented earlier, just keep track of CPU Host Frequency (FSB) speed, Memory Speed (FSB x 2.5) and Memory Voltage. We are going to test to find the following.
Max speed at auto timings and stock manuf specified voltage.
Max speed at auto timings and manuf highest recommended voltage.
Max speed at manual timings and stock manuf specified voltage
Max speed at manual timings and manuf highest recommended voltage.
For example my Corsar XMS is rated at 1.9V in the specifications as a stock voltage but Corsair recommends and warranties it up to 2.1V. As mentioned before, you need to know these values for your ram. Make a post in the memory forum if you have too but rely only on manufactures data sheets or the company representative. Advice from Ub3r_HzAxO8R and his buddies, etc. is to be avoided. If like me, you have more time than money, you can test each stick individually. Its not unheard of to stick a little piece of tape to the stick with the max OC info like "850FSB 544-12@2.1V".
The Memory TEST
Reboot if you have to and get into the BIOS.
From the main menu press the "F12 Key" key and load your "Baseline" profile.
Now enter the "Advanced Chipset Options" sub-menu and check that the first boot device is set to the drive that can boot Memtest.
(Easier than trying to hit the Boot Menu key during restart, hitting "Delete Key" in time is hard enough. )
Find your Memtest CD or floppy and place it in the drive
Go into the M.I.T sub menu and make ONLY the following changes:
CPU Clock Ratio __________________ [6] <<<----Set to 6, all CPU models, for testing
CPU Host Clock Control_____ [Enabled]
CPU Host Frequency (MHz)____________ [Per table below]
System Memory Multiplier (SPD)____ __[Per table below]
DRAM Timing Selectable_______ SPD __ [Auto]
DDR2 OverVoltage Control__ [+0.1] <-- default is 1.8V, 1.8 + 0.1V = 1.9V set this to add up to your ram's manufacturers stock voltage requirement. This example shows my Corsair XMS at 1.9V stock.
Verify that:
Memory Performance Enhance__________ [Normal]
Values in this table will result in a 10% (aprox.)increase in memory speed over stock.
Rating (stock spd)_____ New FSB ___ Mem spd______ New CPU spd
PC2-4300 (533Mhz)_______ 234______( 585) _________ 1.40GHz __ use 2.5 multi
PC2-5300 (667Mhz)_______ 292______( 730) _________ 1.75GHz __ use 2.5 multi
PC2-5400 (675Mhz)_______ 292______( 730) _________ 1.75GHz __ use 2.5 multi
PC2-6000 (750Mhz)_______ 330______( 825) _________ 1.98GHz __ use 2.5 multi
PC2-6400 (800Mhz)_______ 293______( 880) _________ 1.76GHz __ use 3.0 multi
PC2-7200 (900Mhz)_______ 330______( 990) _________ 1.90GHz __ use 3.0 multi
PC2-8000 (1000Mhz)______ 275______(1100) _________ 1.65GHz __ use 4.0 multi
PC2-8500 (1066Mhz)______ 325______(1130) _________ 1.95GHz __ use 4.0 multi
to the main BIOS menu after making the changes above.
From the main BIOS screen press to save your new settings
If a "Testing" profile exists, use your arrow keys and select/highlight it.
If a "Testing" profile does not exist create one by selecting a slot and type in "Testing"
Press to save the baseline + the new settings to the "Testing" profile.
Select/highlight "Save and Exit CMOS", press twice.
OK, I have spent days trying to come up with tables and procedures to step through what needs to be done. Its almost impossible (for me anyway) to come up with anything simple that can cover all situations so we will rely on your brain, as it is the most powerful computer we have available. As mentioned above the point is to find out where your memory starts to have issues at stock timings and voltages. We will then repeat the testing with other timings and voltages but we need to know it all. If you change boards, processors etc. this information is worth its weight in gold. The settings in the table above are agressive, do not become discouraged if you fail the first time.
What to do
Max speed at auto timings and stock manuf specified voltage.
You should have rebooted into memtest. If not, fix it. We are going to slowly raise the CPU Host Frequency (FSB) and each test we will boot into memtest and let it run just the first 3 tests. If memtest gives you no errors, reboot, get into the BIOS and raise the CPU Host Frequency by 3MHz , save and exit, reboot into memtest, and keep repeating this procedure until errors appear. Do NOT change anything else, just the CPU Host Frequency (FSB). Take note of the CPU Host Frequency. Write it down every time you change it because its almost certain the last try will require you to reset the CMOS and the value in the BIOS will be lost. Ok, at some point errors are going to show up. We now have memtest errors, reboot into the BIOS if you can, if not Clear CMOS, boot into the BIOS and load your "testing" profile. Go into the M.I.T menu and put in the last "Good" CPU Host Frequency. Save and exit, and let memtest run for at least one full testing pass. If you get no errors, circle that last "Good" CPU Host Frequency. If you get errors, go back in the bios and reduce the CPU Host Frequency by 2MHz and keep doing this with a memtest run until you get at least 1 full memtest pass with no errors. The CPU Host Frequency you end up with, times the CPU mulitplier from the table that you used for testing gives you the maximum actual speed your memory will pass this test at.