What should I expect from 2500+ AQZEA week 31

hitechjb1 said:

What is the probability of achieving certain level of overclocking
...

(1) Looking at the poll about the Tbred B 1700+ DLT3C in this forum, even there are many unknowns (or randomness, including voltage, cooling, skill, degree of overclocking, margin of errors, ...) about how each number is obtained, but the 360+ data points shows something. As of today (10/18/2003), the distribution centers within the interval 2300- 2400 MHz.
...
Probability for 2101 – 2200 MHz = 11.36%
Probability for 2201 – 2300 MHz = 14.68%
Probability for 2301 – 2400 MHz = 19.94%
Probability for 2401 – 2500 MHz = 18.28%
Probability above 2501 MHz = 11.91 %.

Approximately, it shows the 1700+ DLT3C max overclocking frequency center around 2350 MHz, with a sigma of 125 MHz. Assuming 84.1% of the chips are below 2475 MHz.


(2) Usually, on the average, the Barton does about 100 MHz less (older Barton's are 100-150 MHz less), compared to the DLT3C 1700/1800, so I would extend the distribution for Barton to:

The distribution centers within the interval 2200- 2300 MHz.
...
Probability for 2001 – 2100 MHz = 11.36%
Probability for 2101 – 2200 MHz = 14.68%
Probability for 2201 – 2300 MHz = 19.94%
Probability for 2301 – 2400 MHz = 18.28%
Probability above 2401 MHz = 11.91 %.

Approximately, it means the Barton max overclocking frequency center around 2250 MHz, with a sigma of 125 MHz. Assuming 84.1% of the chips are below 2375 MHz.

...

Click to expand...

hitechjb1 said:

...

Voltage (estimate) needed for overclocking Tbred B and Barton

Assuming HSF, PSU are not the limiting factor, these are my estimate, based on SLK-800/900/947 HS.

1.500 - 1.575 V would get CPU to 2200 MHz (stable) = 200 x 11
1.550 - 1.650 V would get CPU to 2300 MHz (stable) = 200 x 11.5
1.625 - 1.750 V would get CPU to 2400 MHz (stable) = 200 x 12
1.725 - 1.925 V would get CPU to 2500 MHz (stable) = 200 x 12.5
...

Extending them to Barton and DKT3C, I would say usually:
1.650 - 1.725 V would get CPU to 2200 MHz (stable) = 200 x 11
1.700 - 1.800 V would get CPU to 2300 MHz (stable) = 200 x 11.5
1.775 - 1.900 V would get CPU to 2400 MHz (stable) = 200 x 12
1.875 - 2.075 V would get CPU to 2500 MHz (stable) = 200 x 12.5
...

For the 1.6 V rated DUT3C, it would resemble the numbers for Barton/DKT3C.



Related links:

Some numbers to determine max CPU overclocking frequency - Vcore vs temperature,
When do the CPU's slow down? (page 13)
Explanation (page 13)

Overclocking frequency-Vcore break-even point for Tbred B/Barton(page 15)

Click to expand...

deftor said:

Great info on the thread...lots of useful stats..thanks.

btw, what ram timings should i aim for. Its rated 2.5 ram. I have it at 2x3x3x6. should I try for more on these buffalo's

They are voltage hungry right...what would it take to get it to 2x2x2x5?

Click to expand...

Originally posted by hitechjb1
...
In principle, 7-3-3-2.5 should be a little bit faster than 11-3-3-2.5, since the tRAS is smaller.

Active to Precharge Delay (tRAS) is the minimum time for an active access (to perform a single row and column access). It is the least importance for memory performance. Usually 5 or 6 or 7 is fine. tRAS >= Trcd + CAS.

link: RAS, CAS Timing and BIOS Memory Setting

I also heard that for certain memory module, setting tRAS to high number such as 11 would deliver a little bit better benchmark in some cases, especially related to page mode operation in which the memory column access have to be held open/accessed and burst a page of data out through many cycles (hence longer tRAS).

I think that probably is implementation specific for certain memory modules, in combination with memory controller. If indeed shown to work a little bit better, then that is a fact.

But I'll keep the general timing setting for 3200/3500/3700 modules as 6-3-3-2 for CAS2 and 7-3-3-2.5 for CAS2.5 as initial setting.

Click to expand...