Unfortunately, we couldn’t succeed in overclocking a dual-core CPU on DFI LANPARTY LT X48-T2R mainboard. But maybe the board would do well with a quad-core processor? We decided to check things out using a new weapon: the youngest quad-core 45nm Intel Core 2 Quad Q9300 (2.5GHz, 333MHz FSB, 6MB, Yorkfield, rev. M1).
This is a new processor, we haven’t yet studied its overclocking potential very carefully. So far we have only tested it on abit IP35 Pro mainboard. Yes, this is no mistake: on abit IP35 Pro. The thing is that abit has finally released a new BIOS version 1.6 for their IP35 Pro mainboard that allows using fractional clock frequency multipliers for 45nm processors. However, despite the long six months it took them to do this, the new BIOS version looks more like a beta than a complete release.
To check out the processor features without hitting against its overclocking potential, we reduced its clock frequency multiplier to the minimal x6. However, when we booted Windows, we often discovered that for some reason the multiplier was set at x7 or even at the maximum possible x7.5! It turned out that abit IP35 Pro mainboard may change the processor multiplier on its own at any time. It was pretty absurd, when we set all parameters including the x6 multiplier in the BIOS Setup, pressed F10 (save and quit) and when the system wanted us to confirm the operation returned to the previous page to see that the multiplier has already been changed to x7!
Of course, this unpredicted behavior of abit IP35 Pro mainboard made things more complicated. But it could really overclock processors, we can’ take that away from it. Despite all the problems, we managed to get Intel Core 2 Quad Q9300 to work at 475MHz FSB with the default multiplier of x7.5. This result doesn’t look final, I don’t feel like saying that our CPU overclocked to 3562.5MHz (475x7.5). 3.6GHz looks much more attractive and can be reached at 480MHz FSB. So we will go for it.
Unfortunately, DFI LANPARTY LT X48-T2R mainboard didn’t help us to overclock our Intel Core 2 Quad Q9300 to 3.6GHz. It didn’t have any problems with spontaneous multiplier increase, but at 475MHz FSB with the x6 multiplier it could only start, but failed to boot Windows. The same happened at 465MHz FSB and even 460MHz FSB. We managed to start Windows at 460MHz FSB when we enabled GTL REF Voltage Control in the mainboard BIOS, but the system still froze dead when we launched Prime95 stability check. Only when we dropped the bus frequency to 455MHz, we could work normally for some time, which is hardly a satisfactory result for an overclocker solution.
By the way, you may have noticed that our Intel Core 2 Quad Q9300 processor features impressively low default Vcore of only 1.17V or 1.175V. We couldn’t be happier that our quad-core processor worked at pretty high frequencies with such low nominal voltage setting, but only not with DFI LANPARTY LT X48-T2R mainboard. You remember that CPU VID Special Add parameter doesn’t work until you increase CPU VID Control above 1.2V with a 45nm CPU, don’t you? But our processor has even lower nominal voltage. We increase CPU VID Control, set CPU VID Special Add at the desired rate, lower CPU VID Control to the nominal, but since 1.17V is lower than the required 1.2V CPU VID Special Add will be reset to Auto.
As a result, it turns out that we cannot use CPU VID Special Add to overclock our processor as well as any other 45nm processor with nominal Vcore below 1.2V and a 65nm processor with nominal Vcore below 1.3V. We will have to use CPU VID Control to increase the processor core voltage, i.e. it will not drop in idle mode, Intel power-saving technologies will not work, the processor fan will have to rotate at higher speed all the time.
