Overclocking Performance
Our tests attempt to determine the following three overclocking limits: motherboard, memory, and ideal.
 
To figure out the maximum overclock for the motherboard, we drop memory timings, frequencies, and the CPU multiplier, and throttle up the system bus until it can no longer run our suite of tests (the same tests used throughout this article, takes about 2 hours).
 
For memory overclocking, we set the memory multiplier to a 1:1 ratio with the system bus, set the CPU multiplier lower, and then bump the system bus until the memory can not maintain a stable system.
 
Finally, the ideal overclock test attempts to find a good combination of bus frequency, CPU and memory overclock settings.
 
Overclocking Configuration

 
 CPU  Voltage  1.65V (+0.15 V)
 Memory Voltage  2.7V (+ 0.2 V)
 Chipset Voltage  1.20V (+0.1 V)
 Memory Timings  3-2-2-2T

 
Motherboard Overclock

With a CPU multiplier of 6x, 800MHz HTT, and lax memory timings, we proceeded to pump up the system bus. I started at 230 MHz, and incremented by 10 MHz doing a 8MB SuperPi calculation to determine stability before proceeding.

CPU Multiplier 6x 
HT Bus 600 MHz
Memory Speed 100 MHz (2:1 Bus:Mem)

 
Once past 290 MHz, I started to get a little nervous – high bus frequencies can sometimes have unpredictable effects if overclocking fails. Pushing forward… 300 … 310 … 315 …. 357 MHz!!!
 
At 357 MHz, the system successfully ran all our benchmarks without an issue. While 2 hours of testing isn’t enough to really confirm if it’s 100% stable at that frequency, it does give a good ballpark number.

CPU Multiplier Overclock
6x 357 MHz 
8x 320 MHz
10x 265 MHz

Increasing the CPU multiplier to 8x, the overclock drops to 320 MHz. At 10x, it’s 265 MHz.
 
All these numbers are very impressive.
 
Memory Overclock


CPU Multiplier 6x 
HT Frequency 800 MHz, 600 MHz 
Memory Bus 200 MHz (1:1 Bus:Mem)
Overclock @ 800 MHz HT 214 MHz
Overclock @ 600 MHz HT 215 MHz

Overclocking the memory on the EP-9U1697 fell short of expectations. In past reviews, we have seen this pair of Corsair XMS RAM capable of 230 – 235 MHz at 2.5 CAS settings. So we should expect similar on the EP-9U1697 right? I was only able to get roughly 214 – 215 MHz before SuperPi gave errors.
 

EPoX EP-9U1697 GLI Motherboard Review - SLI Killer? - Motherboards 66
A modest RAM overclock of 215 MHz or higher gave the EP-9U1697 problems.
This RAM is capable of 230MHz and higher.

Changing the HTT, CPU, and memory multipliers didn’t change anything – 215 MHz was the absolute max. A bit of a let-down after the extraordinary overclocking of the motherboard. At bus speeds higher than 215 MHz, SuperPi would give errors.

At 600 MHz HT, the results were the same: memory overclock was limited to 215 MHz.
 
Other reviewers of the EP-9U1697 did not have problems with memory overclocking, so I’m left thinking it’s a problem with my configuration.
 
Ideal Overclock

The “ideal” overclock is a bit subjective. For me, the ideal overclock is the highest attainable CPU frequency with the RAM in a 1:1 ratio if possible. From the memory overclock results above, I knew that getting the system to overclock above 215 MHz was going to be a challenge.

CPU Multiplier 12x, 11x 
HT Frequency 1 GHz, 800 MHz
Memory Bus 200 MHz, 166 MHz


The highest overclock at 12x was 215 MHz (as predicted) for a resulting CPU speed of 2580 MHz, and the memory at 215MHz. Anything higher and I would get errors while running SuperPi. Dropping the HT to 800MHz did not help achieve a higher overclock.

At 11x CPU, 1 GHz HT, and the memory at 166MHz, I managed to get 238 MHz before 3DMark 06 started to stutter and struggle. From 238 MHz to 245 MHz, the system still ran and completed majority of the benchmarks, but 3DMark 06 kept aborting.

Here are some results of the benchmarks I ran during this test:

EPoX
EP-9U1697 GLI

EPoX 
EP-9NPA+ SLI

Overclock (MHz) 200 215 238 240 200
CPU Multiplier 12 12 11 11 12
CPU Frequency (MHz) 2400 2600 2621  2643  2400
Memory Bus Speed (MHz) 200 200 166 166 200
Memory Frequency (MHz) 200 215 198 199 200
HT Frequency (MHz) 1000 1000 1000  800 1000
SiSoft Sandra

CPU – ALU

10719 11470 9821 10458 10775

CPU – iSSE3

4871 5196 4458 4736 4872

Memory – Float

4918 5257 3871 4129 4814

Memory – Int

4919 5255 3869 4124 4815
PCMark 05 3769 3833 3803 3541 3846
3DMark 06 (Single / SLI) 1302 / 2299 1301 / 2330 1322 / 2332 1306 / 2282 1521 / 2724

SM 2.0 (Single / SLI)

491/ 894 470 / 906 487 / 904 470 / 855 591 / 1166

HDR / SM 3.0 (Single / SLI)

476 / 942 490 / 940 491 / 942 493 / 942 557 / 1079

CPU (Single / SLI)

930 / 928 996 / 984 989 / 994 1003 / 1004 923 / 934
Call of Duty 2

Min (Single / SLI)

24 / 35 23 / 36 23 / 34 23 / 34 28 / 37

Avg (Single / SLI)

34 / 45.4 34.7 / 54.3 33.9 / 43.9 32 / 56.4 42 / 46.7
Quake 4

Min (Single / SLI)

38 / 73 38 / 73 37 / 71 34 / 65 40 / 60

Avg (Single / SLI)

87.3 / 125 87.9 / 123.4 85.5 / 120.9 79.2 / 110.5 93 / 124.27

Clearly the best results were achieved when the CPU was using a 12x multiplier and the memory and bus were synchronous. A 10 FPS boost in Call of Duty when in SLI mode at 12×215 compared to 12×200 is definitely worth attempting for an overclocker.
« PreviousNext »