Rule of thumb for intel is 1 channel/2 physical cores; so while it's massive overkill for the downbinned quadcore part and a bit more than than is needed for this years hexcore, if they launch an 8 core IB-E chip next year it will need all 4 channels. This would be the same thing they did when making LGA1366 triple channel despite only launching with quads.
True, but I remember when overclocking was stupid simple (Celery days) - multiplier x bus clock speed = how fast you're now running. I also remember burning out that CPU in 2 years running at 450 MHz rather than the 300 MHz it was "specced" for.
I suppose as things get more complicated as bus speed kind of disappeared and was no longer tied with RAM speed, and things became more independent of your PCI bus speed (which was a percentage of your bus speed).
Either way, overclocking kind of passed me by a while ago. It just doesn't matter to me anymore. I'm looking more for "fast enough" with more stability.
I made an application to calculate the overclock so you don't have to do all the calculations every time.
The only tweak i did was to round-down step 2 so if you try 4200MHz the multiplier will be lower (x33) and the BCLK slightly higher (101.82) which should give better performance. I might change this though with future releases and when i'm 100% sure about the available memory multipliers (i assumed x10.6 x8 x13.33, x16 and x1866 since it's the only way to get ddr3 800,1060,1333,1600 and 1866 MHz support at x1 RCR and stock BCLK) With the program the aim was to get the best overclock without having the ram overclock to crazy speeds because of the RCR.
I7 core 3820 (quad-core) standard CPU Settings: 3,6 Ghz =3600 Mhz standard mem Settings: 1600 Mhz standard CPU Multiplier: 36x RCR: (1.00x, 1.25x of 1.66x) ~ Cpu strap in Asus Bios (100mhz, 125mhz, 166 mhz) A CPU Strap of 166 mhz is NOT recommended) Ratio cpu/mem = 3600Mhz / 1600Mhz = 2.55 Available mem multipliers i7 core 3820: 8x/10.66x/13.33x/16x/18.66x/21.33x/24x/26.66x
New Settings formule: 1. Frequency / Reference clock ratio = X 2. X / 100 = CPU multiplier 3. X / CPU multiplier = BCLK 4. BCLK x RCR = (New) BCLK 5. Mem Frequency = (New) BCLK) x Mem Multiplier
Test 1: (166 Mhz CPU Strap is NOT recommended according to Asus, not all CPU's support it) Reference clock ratio = 1.66x (CPU Strap = 166 mhz) New Overclock Target = 4.7 Ghz New ideal Target dimm frequency = 4700 / 2.55 = 1843 Mhz 1. 4700 Mhz/RCR 1.66 = X = 2831 2. X= 2831 / 100 = 28,31 ~ 28x 3. X= 2831 / 28x = BCLK = 101.1 4. 101.1 x 1.66 = 167.8 mhz ~ (New BCLK 167) 5. 167 x 10.66 = 1780 Mhz ~ 1800/1866 DDR3 Dimms
In Asus BIOS: Cpu Strap = 125 CPU multiplier = 28 new BCLK = 167 CPU Frequency = 167 * 28 = 4676 MHz Mem Frequency = 1780 mhz
TEST 2: (Ilike this configuration best, good ratio and speed) Reference clock ratio = 1.25x (CPU Strap = 125mhz) New Overclock Target = 4,7 Ghz New ideal Target dimm Frequency = 4700 / 2.55 = 1843 Mhz 1. 4700 Mhz/RCR 1.25 = X = 3760 2. X= 3760 / 100 = 37.6 = 37x but 36 is maximum. 3. X= 3760 / 36x = BCLK = 104.4 4. 104.4 x 1.25 = 130,5 mhz ~ (New BCLK 130) 5. 130 x 13.33 = 1733 mhz ~ 1800/1866 DDR3 Dimms
In Asus Bios: CPU Strap = 125 Mhz CPU multiplier = 36 new BCLK =130 MHz CPU Frequency = 130 * 36 = 4680 MHz Mem Frequency = 1733 Mhz
TEST 3: (The most stable BCLK, But Mem overclock is probably less good, i dont like it) Reference clock ratio = 1.25x New Overclock Target = 4,5 Ghz New ideal Target dimm Frequency = 4500 / 2.55 = 1764 Mhz 1. 4500 Mhz/ RCR 1.25 = X = 3600 2. X= 3600 / 100 = 36x (default) 3. X= 3600 / 36x = BCLK = 100 4. 100 x 1.25 = 125 Mhz ~ (New BCLK 125) 5 125 x 13.33 = 1666 Mhz ~ 1600 DDR3 Dimms
In Asus Bios: CPU Strap = 125 Mhz CPU multiplier = 36 new BCLK =125 MHz CPU Frequency = 125 * 36 = 4500 MHz Mem Frequency = 1666 Mhz
Conclusion: Test 2 seems the more logic and wise setting to me . with the 1800/1866 DDR3 Quad kit and ~ 4,7 Ghz speed
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11 Comments
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Filiprino - Wednesday, September 21, 2011 - link
This means overclocking similar to past times.ajp_anton - Wednesday, September 21, 2011 - link
Seems like a waste of memory channels if they also force you to overclock it.2213MHz quad channel is like 4426MHz dual, overkill anyone?
DanNeely - Wednesday, September 21, 2011 - link
Rule of thumb for intel is 1 channel/2 physical cores; so while it's massive overkill for the downbinned quadcore part and a bit more than than is needed for this years hexcore, if they launch an 8 core IB-E chip next year it will need all 4 channels. This would be the same thing they did when making LGA1366 triple channel despite only launching with quads.Assimilator87 - Wednesday, September 21, 2011 - link
So you basically need a PhD in math to overclock this thing.pewter77 - Wednesday, September 21, 2011 - link
i wouldn't say three arithmetic operations constitutes needing a PhD in math....more like kindergarten math or 1st grade.
erple2 - Thursday, September 22, 2011 - link
True, but I remember when overclocking was stupid simple (Celery days) - multiplier x bus clock speed = how fast you're now running. I also remember burning out that CPU in 2 years running at 450 MHz rather than the 300 MHz it was "specced" for.I suppose as things get more complicated as bus speed kind of disappeared and was no longer tied with RAM speed, and things became more independent of your PCI bus speed (which was a percentage of your bus speed).
Either way, overclocking kind of passed me by a while ago. It just doesn't matter to me anymore. I'm looking more for "fast enough" with more stability.
MrSpadge - Thursday, September 22, 2011 - link
I hope for everyone you don't have a math PhD..dfghdfshhh - Friday, September 23, 2011 - link
Come go and see, will not regret it Oh lookhttp://www。benzlogo。com
zhangqq - Monday, October 31, 2011 - link
http://ygn.me/bTf7pfcento - Monday, October 31, 2011 - link
I made an application to calculate the overclock so you don't have to do all the calculations every time.The only tweak i did was to round-down step 2 so if you try 4200MHz the multiplier will be lower (x33) and the BCLK slightly higher (101.82) which should give better performance.
I might change this though with future releases and when i'm 100% sure about the available memory multipliers (i assumed x10.6 x8 x13.33, x16 and x1866 since it's the only way to get ddr3 800,1060,1333,1600 and 1866 MHz support at x1 RCR and stock BCLK)
With the program the aim was to get the best overclock without having the ram overclock to crazy speeds because of the RCR.
Here is the link for the program, i hope you like it http://www.mediafire.com/?3d44j6kw0waeeac
Here is a screenshot http://goo.gl/SzmSw
Follow me on twitter @fcento for updates
Andre Keurentjes - Thursday, November 24, 2011 - link
I tried a few things and changed the formules a bit, correct me or comment plz.I like Feedback.
"ASUS X79 and Sandy Bridge E Overclocking Guide" video i found helpfull on YOU TUBE.
http://www.youtube.com/user/asusrog#p/u/10/Kx2z07s...
I7 core 3820 (quad-core)
standard CPU Settings: 3,6 Ghz =3600 Mhz
standard mem Settings: 1600 Mhz
standard CPU Multiplier: 36x
RCR: (1.00x, 1.25x of 1.66x) ~ Cpu strap in Asus Bios (100mhz, 125mhz, 166 mhz)
A CPU Strap of 166 mhz is NOT recommended)
Ratio cpu/mem = 3600Mhz / 1600Mhz = 2.55
Available mem multipliers i7 core 3820: 8x/10.66x/13.33x/16x/18.66x/21.33x/24x/26.66x
New Settings formule:
1. Frequency / Reference clock ratio = X
2. X / 100 = CPU multiplier
3. X / CPU multiplier = BCLK
4. BCLK x RCR = (New) BCLK
5. Mem Frequency = (New) BCLK) x Mem Multiplier
Test 1: (166 Mhz CPU Strap is NOT recommended according to Asus, not all CPU's support it)
Reference clock ratio = 1.66x (CPU Strap = 166 mhz)
New Overclock Target = 4.7 Ghz
New ideal Target dimm frequency = 4700 / 2.55 = 1843 Mhz
1. 4700 Mhz/RCR 1.66 = X = 2831
2. X= 2831 / 100 = 28,31 ~ 28x
3. X= 2831 / 28x = BCLK = 101.1
4. 101.1 x 1.66 = 167.8 mhz ~ (New BCLK 167)
5. 167 x 10.66 = 1780 Mhz ~ 1800/1866 DDR3 Dimms
In Asus BIOS:
Cpu Strap = 125
CPU multiplier = 28
new BCLK = 167
CPU Frequency = 167 * 28 = 4676 MHz
Mem Frequency = 1780 mhz
TEST 2: (Ilike this configuration best, good ratio and speed)
Reference clock ratio = 1.25x (CPU Strap = 125mhz)
New Overclock Target = 4,7 Ghz
New ideal Target dimm Frequency = 4700 / 2.55 = 1843 Mhz
1. 4700 Mhz/RCR 1.25 = X = 3760
2. X= 3760 / 100 = 37.6 = 37x but 36 is maximum.
3. X= 3760 / 36x = BCLK = 104.4
4. 104.4 x 1.25 = 130,5 mhz ~ (New BCLK 130)
5. 130 x 13.33 = 1733 mhz ~ 1800/1866 DDR3 Dimms
In Asus Bios:
CPU Strap = 125 Mhz
CPU multiplier = 36
new BCLK =130 MHz
CPU Frequency = 130 * 36 = 4680 MHz
Mem Frequency = 1733 Mhz
TEST 3: (The most stable BCLK, But Mem overclock is probably less good, i dont like it)
Reference clock ratio = 1.25x
New Overclock Target = 4,5 Ghz
New ideal Target dimm Frequency = 4500 / 2.55 = 1764 Mhz
1. 4500 Mhz/ RCR 1.25 = X = 3600
2. X= 3600 / 100 = 36x (default)
3. X= 3600 / 36x = BCLK = 100
4. 100 x 1.25 = 125 Mhz ~ (New BCLK 125)
5 125 x 13.33 = 1666 Mhz ~ 1600 DDR3 Dimms
In Asus Bios:
CPU Strap = 125 Mhz
CPU multiplier = 36
new BCLK =125 MHz
CPU Frequency = 125 * 36 = 4500 MHz
Mem Frequency = 1666 Mhz
Conclusion:
Test 2 seems the more logic and wise setting to me .
with the 1800/1866 DDR3 Quad kit
and ~ 4,7 Ghz speed