Print PDF
User Rating: / 4
PoorBest 

Lesson 07 - Overclocking the RAM and lowering the RAM's timings

Introduction

In this lesson we will show how to find your memories fastest stable speed.  Since the memory multiplier is unlocked on both Black Edition and non Black Edition CPUs the process for finding your memories highest stable frequency is the same for both.  We will also show a different way to improve your RAM's performance by instead lowering it's timing settings.

Setting up the BIOS for Testing

We're back in the BIOS and we're going to set it back to the default profile we made in Lesson 3.  We have our memory set to 1600MHz because it is rated to run at 1600MHz.  If we go to change the multiplier it's current setting of 8X is the highest available.  In order to find our memories maximum stable speed we are going to have to leave it set at 8x and use reference clock increases to raise the memory frequency.  200MHz on the reference clock times the memory multiplier of 8 gives use the current RAM speed of 1600MHz.  

The memory probably won't be stable at anything above 1900MHz regardless of how much we increase the voltage to the RAM.  1900 divided by the memory multiplier of 8 gives us a maximum reference clock speed of 237.  I'll set the reference clock to 237MHz and I'll need to lower the multipliers for the CPU, CPU Northbridge and HT Link so that with this reference clock frequency they will be at or below their stock speeds.  This will ensure that we are only stressing the RAM and that overclocking it will be the only cause of instability. 

If you have 1333MHz RAM it may work at up 1600MHz. You never know unless you try.  You need to stick with the 6.66 multiplier.  A reference frequency of 200MHz times the multiplier of 6.66 give you 1333MHz.  1600 divided by 6.66 is 240 so you would set your reference clock to 240MHz and then lower the CPU, CPU Northbridge and HT Link multipliers so they are at or below their stock settings.  I actually have 1600MHz rated RAM so I'll set the speed back to 237 and set the multipliers again.  We'll scroll down here and check the RAM voltage.  My RAM's stock voltage is 1.5V and that is fairly standard.  My RAM can run at up to 1.8V, also fairly standard.  You'll want to check your RAM's rated voltage range, start at the stock voltage and make sure you don't go over it's maximum rated voltage to keep from damaging the RAM. I'll set the reference frequency back to 200MHz, hit esc and F11 to save these settings in a new profile.  I'll call it RAM OC settings. 


Overclocking the RAM

If you have watched all of the previous lessons and especially if you have already done some overclocking following these videos this procedure will be like second nature to you by now.  We need to increase the frequency of the memory by about 50MHz at a time.  For my 1600MHz rated memory I'll divide 50 by the memory multiplier of 8 and I get 6.25. If I increase the reference clock by 6MHz that gives us a RAM frequency increase of 48MHz.  If you have 1333MHz rated memory you would divide 50 by the memory multiplier of 6.66 which give you 7.5 and if you increase your reference clock speed by 7MHz you will get a RAM frequency increase of 47MHz.  

Our reference clock is set to 206MHz giving us a 1648MHz memory speed. We would then hit F10 and save, go into Windows and run Prime95 on the Blend setting for at least 20 minutes and or the memory test in BurnInTest.  If the system remains stable{reg}, come back into the BIOS and increase the RAM speed by another roughly 50MHz and keep testing until the system fails with an error in Prime95. The green icons will turn red if it fails, or if the system freezes, blue screens and or reboots itself.  Then go into the BIOS and increase the RAM voltage by .05V and Prime95 Blend test and or memory test in BurnInTest again at the speed that previously failed.  

Continue using this method of speed increase along with small voltage increases as needed to find your RAM's maximum stable speed. As you get to the high end of speeds your RAM is capable of you should only increase the reference clock speed 1MHz at a time.  This will let you find your RAM's absolute fastest stable speed. Be sure to keep notes along the way of each stable speed along with the amount of voltage required to make each speed stable.

On my system the RAM's maximum stable speed was 1792MHz at 1.75V.  Further voltage increases did not allow me run the RAM any faster. However the system was also stable at 1752MHz with voltage at stock 1.5V.  In my case the 40MHz speed improvement is not worth the extra .25V going to the RAM and potentially reducing it's lifespan.  I'll stick with 1752MHz at 1.5V as my reasonable maximum stable RAM speed.  


Lower the CAS Timings to increase performance

Another route we can take to improve the RAM's performance is to lower it's timing settings.  That means we will decrease the time the RAM spends waiting between each operation.  To do this we need to go back to the BIOS and Press 12 to load the default profile.  This has all of the CPU and RAM settings set manually at their default.  You'll remember in Lesson 3 we manually set the CAS timings to 9 9 9 and 24.  This is the lowest CAS timings my RAM is rated for.  

I'd like to see if it will actually work on a lower setting.  8 8 8 and 24.  We have the voltage set to our RAM's default which is 1.5V.  You would then save and exit and run Prime95 on the Blend setting and or the memory test in BurnInTest to see if it's stable.  If it is that's great, try lowering the timings to 7 7 7 and 24 and test again.  If the system was't stable at 8 8 8 and 24 timings we would increase the voltage .5V at a time, testing in Prime95 on the Blend setting and or memory test in BurnInTest, with each voltage increase until the system is stable.  Next you can try decreasing the 4th number 24 in our case, down to say 21 and test again.  If the system is stable try 20 or 19, much lower probably isn't possible.  Increase the RAM voltage as needed but remember your RAMS maximum safe voltage.

The last latency setting you can try to lower is the 1T/2T Command Timing.  The default is almost always 2.  1 is better.  Lower it to 1 and run the stability tests again in Windows.  Increase the RAM voltage if you need to to make the system stable.  There's a possibility that no amount of increased voltage will allow you to lower your RAM's timings.  This is OK because the majority of performance increases come from the other components you've already overclocked. On our system the RAM is stable at 8 8 8 and 21 with a Command Timing of 1T.  This is with the RAM voltage at stock 1.5V. 


Overclock, Lower the Timings or both?

You can use either of these methods on your system or combine them, though combining both RAM overclocking and CAS timing tightening can be very time consuming to test because there are so many variables.  I would recommend lowering the CAS timings if you have 1600MHz RAM.  If you get the CPU Northbridge speed up to 2400MHz, a RAM speed of 1600MHz is perfect and the lower timings will improve performance. If you have 1333MHz memory I would recommend overclocking the RAM but you could go the timings tightening route and see which improves performance more.

In the next lesson we are going to put together all of the overclocking we've been doing into one configuration that will overclock the CPU, CPU Northbridge, HTLink and memory.


Warning: include(/home/hpcb/homepcbuilder.com/includes/calendar.php) [function.include]: failed to open stream: No such file or directory in /home/hpcb/homepcbuilder.com/templates/yoo_phoenix/index.php on line 269

Warning: include() [function.include]: Failed opening '/home/hpcb/homepcbuilder.com/includes/calendar.php' for inclusion (include_path='.:/usr/local/php5/lib/php:/usr/local/lib/php') in /home/hpcb/homepcbuilder.com/templates/yoo_phoenix/index.php on line 269