Enabling Hyperthreading on non Hyperthreaded p4'2

[tweaked 0]

Quote:

Just one day before launch of Intel fastest 3.06Ghz Pentium 4, RiStaR has managed to turn on the Hyper-Threading function by chance on the older Pentium 4 2.4B using the IWILL P4HT-S 845PE board. This has proven that Hyper-Threading was already present in the Northwood just that it has been disabled by the BIOS. There should be some tricks to enable HT in the BIOS even it is not a 3.06Ghz P4.

wooot!
I knew this could be done!
Somewhere in one of my prevous posts i theorized about the possibility of enabling HT on older p4's. I wonder how well that is working for him?

If i can hack my P4 2.4 to enable HT i will be very happy camper.

RiStaR needs to share the info on how he did this.

anyone have more info, theories, etc, etc???

[adamvjackson 0]

I had previously recieved an email from an Intel rep (this was about 3 months ago) that confirmed that Hyperthreading was present in all of the 'B' revision P4's (533MHz bus) and could be enabled at a later date with a bios update.

[tweaked 0]

of course i have an "A" revision cpu with a 400 mhz fsb. ;(

[clutch 1]

I thought this was general knowledge anyway, or maybe I just thought it was. In any case, I will have to take a look at my P4PE and see if it will work. I *just* installed WinXP after a nasty tumble with Debian (Unstable branch) so I didn't have a need to try it. If anyone else gets a chance to, post your results.

 

One more thing, if you have an app that supports SMP, but manually, do you think it will work alright using HT? I wonder how Q3 would behave in this case.

[adamvjackson 0]

Clutch: for what it's worth, I have a statusbar on the top of my screen with a graph of the past 10-15 seconds of CPU activity; Whenever I exit Quake 3 (on my P4 2.26) the CPU cycles are always at 100%, and I have seen this on other machines, too, which leads me to believe that the Quake 3 engine will all available CPU cycles. I would also think that only SMP-enabled/SMP-optimized applications could take advantage of hyperthreading, in reality, I don't know how much of a difference it will make. Either way, there's only one physical processor, and with computing, among other things, you're always limited first and foremost by the physical layer. Also, I do plan on enabling hyperthreading for my machine, but I believe I will wait for an official BIOS update to enable it, the possibility of reducing system stability is not worth the possible performance gain, IMO.

[sapiens74 0]

With the new P4PE bios, it still doesn't give an option to enable it.

 

I'm sure if it is indeed available, someone could mod a bios to do so

[tweaked 0]

yeah, my p4t533-c has support for HT, but it doesnt have the bios setting unless the mobo detects it. From what i hear (warning! conjecture and rumor!) the p4 has the ummm tag on the cpu that HT is present disabled on the die... theorectically you should be able to just force the bios to enable HT.

 

According to my Intel rep (i am not trying to start a "my rep is better than yours" war, just saying where my info comes from) HT is present and functional in all northwood and better p4's not just the 533 fsb version.

 

Supposedly Intel burned out the HT part of the die in the older p4's (like 486sx's burned off math coproc), but when they moved to the northwood it was easier and more economical to just burn the tag that tells the mobo HT is present.

 

FYI, my intel dude is just a sales/advertising rep... but he has given out accurate info in the past.

 

sooo...

i am willing to trash my system a bit and start hacking my bios...

anyone care to point me in the right direction as to programs to use, etc, etc?

[BladeRunner 0]

OK people, there seems to be a real lack of knowledge here about HT and what you need to enable it.

 

Number one on this list is a CPU that can have HT enabled.

This is the 3.06Ghz ONLY.

"But the link at the top, they said......."

No, they are using an ES (Engineering Sample) version of the CPU, this is not something you can go and pick up from your local vendor.

Take a look here:

 

http://www.vrforums.com/showthread.php?threadid=5525

 

Now I hate to be the bringer of bad news, but here it is:

The current Northwood A & B CPU's (with the exception of the 3.06Ghz) CANNOT have HT unlocked.

It is burnt on the die (like the 486sx CPU was the same as the 486DX CPU with traces broken).

 

The three things you need to have a HT enabled system are as follows:

 

1. A chipset that supports HT, numerous ones do and anything released now will.

2. A BIOS that enables HT, using the list of HT compatible chipsets, a lot of BIOS upgrades will be released that enable HT.

3. A CPU that has HT enabled, currently only the 3.06Ghz - lower frequency CPU's may have them IF Intel decide to manufacture them, which seems unlikely (Like when they released Northwood they released a 1.6Ghz Northwood even though they were already up to 2Ghz).

 

This is the only way to get HT.

Current Northwood A's and B's will not be HT enabled.

[clutch 1]

Well, while never being a big fan of Tom's Hardware (I used to be a long time ago), this review does show a fair amount of data with respect to enabling HT:

 

http://www.tomshardware.com/cpu/02q4/021114/index.html

 

This does behave a lot like a normal dual-cpu system. I think something like this will payoff for the majority of users in this forum as we tend to run *many* applications at the same time. BTW, the video clip is worth watching if you have broadband to get it.

[BladeRunner 0]

*Nods*

And even that site shows it is only the 3.06Ghz P4 which is HT enabled, nothing about the slower CPU's.

 

It's a nice enough idea and I'm sure it will take off - so long as none HT enhanced programs do not take a perfromance hit then I'm sure it will be a good selling point.

Although I do feel that anybody jumping onto the HT bandwagon at the moment (spending all that money on a 3.06Ghz at release) has far more money than they need.