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Fastest AM3 mb challenge.

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Here's my 720's best run so far on water - Didn't help that was done last July but almost got 4.4 from it.
http://hwbot.org/community/submission/1025929_bones_cpu_z_phenom_ii_x3_720_be_4389.3_mhz

The reason for the rejected result is explained and I'm hoping the next time around this doesn't happen. Should be able to hit at least 4.4 no prob with better cooling but for now, H2O is all I have for it.

I also believe the board may be holding it back somewhat.
 
you HTLink (incorrectly labeled FSB) is much higher then what you need. You might be only getting instable past 4.2 because your HTL is 2400. You only need it around 1800 - 1900 unless you have quad beast gpu's.
 
My methodology for working out my overclock was to only look at one item at a time. So I worked out the max overclock I could get by raising the multiplier only. Then I went back and worked out the fastest FSB bus speed that was stable (which was ~350MHz). Then it was a case of playing with multipliers and FSB speeds that would give me a higher than stock HT speed, while running my RAM in spec and hitting the 4.2GHz ceiling I seem to have reached.

The temps in HW monitor are around 44-45°C, but I'm reluctant to push any more volts through the CPU than I am already. I worked out a rough offset for Coretemp (idling the processor at 800Mhz and looking at the CPU core temp, then looking at ambient temp in the room, subtracting the two and adding 5° to the difference, to give me a 13° offset), which suggests the Coretemp could be as high as 52°C under P95 stress testing. Not sure if AMD's figure of a safe max temp of 62°C is core temp or the value read by the motherboard diode under the socket.

Cooling is a Thermochill TA120.3 with 3 undervolted Noctua fans, an Aquacomputer cuplex kryos HF waterblock and a Laing DDC pump with an Alphacool top. Case is a Corsair 700D. Rear intake fan is a Noctua 140mm fan running undervolted and flipped around as an intake, supplying cooler air to the radiator (doing this was worth about 3° improvement on load temps).

*edit* I tried running with an FSB of 200MHz and a multiplier of 21 and I lost about 1500MBps in bandwidth (RAM was at 1333MHz, it went from 10500 down to about 9000, using Everest's benchmarking functions). I then tried running the RAM at 1600MHz (same as it was at the higher FSB speed) and this wasn't much better. In other words, the 400MHz on the HT is worth about 15% extra bandwidth on memory speed. I've since nudged the CPU voltage upslightly and bumped the multiplier up a notch to give a clock speed of 4320MHz and left it running a blend stress test in P95.

*2nd edit* just noticed that it shows my OS as Vista Business SP2, which is wrong. I'm running 7 Pro SP1.

*3rd edit* 4320 was a step too far and the system was not P95 stable, even pushing the voltage up to 1.6V, so I think I'll stay happy at 4.2GHz. The temps weren't bad, still under 50°C, but I was getting very nervous about putting too much voltage through my CPU.
 
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Its not your HTL contributing to higher memory bandwidth, it would be your cpuNB speed and Ref clock. AMD chips have an on-die memory controller (IMC), that can be overclocked by upping the cpuNB speed and Ref clock. The HT Link is more like a bus for PCIe devices and whatnot. Most people here will recommend HTL speeds around 1800-1900. Read Dolk's PhenomII guide in my sig to learn more about the IMC and OC'ing your Thuban.
 
Definitely what Dooms said is true. High HTlink is not good, but neither is low. You just need to find a sweet spot for it. Usually for me, I run 2200-2400 and occasionally higher.
 
ChanceCoats123 said:
Definitely what Dooms said is true. High HTlink is not good, but neither is low. You just need to find a sweet spot for it. Usually for me, I run 2200-2400 and occasionally higher.
Click to expand...

2400 is around where I have it, but it looks as though there may be some merit in pushing the CPU-NB speed a bit higher. Dolk's guide seems to suggest that it is more stable to keep the HTT and CPU-NB speeds the same (it's in his section on Thuban overclocking).

I've been on Intel for the last three years, so the concept of different buses is one I'm having to take some time to get my head round. Before that I had an Athlon x2 4400, where there was only a HTT bus to worry about, so things were much simpler then!
 
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Well the HTLink is like a normal bus, it connects the CPU to other thins on the board, like the chipset. The cpuNB speed is the bus for controlling (among other things I think) memory tranfers. So... a high cpuNB can yield better memory performance and also better cpu cache performance.
 
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