Some time ago, a mysterious CPU showed up at the OS/2 Museum:
Intel CPU, S-spec SL7HY
It is a Socket 775 CPU with a Pentium 4 label and the following markings: 3.73 GHZ/1M/1066/A4. In other words, 3.73 GHz clock speed, 1 MB L2 cache, 1066 MHz FSB, and A4 power/TDP requirements (should be mere 84W TDP according to Scott Mueller). The S-spec of the CPU is SL7HY. The processor was manufactured in week 22 of 2004, long before the fall of the evil heat-dissipating NetBurst empire.
Okay, so this is one of the faster-clocked Pentium 4 CPUs, perhaps with an “extreme” FSB speed, but what’s so unusual about it?
What’s unusual is that there is no known Intel CPU with these characteristics, and the S-spec is completely unknown. It’s not a qualification or engineering sample processor; the S-spec suggests a standard production CPU, and there are no SECRET/CONFIDENTIAL markings either. The processor is not unheard of, but it’s a little strange.
It’s instructive to see what CPU-Z thinks about the CPU:
CPU-Z statement on SL7HY CPU
Xeon? Not if the labeling on the CPU is to be believed. Socket 604? Uhh, nope. Calling the CPU Nocona is not too far off the mark, if we ignore the fact that there were no Nocona CPUs with 1066 MHz FSB. But Nocona processors were 90nm Prescott relatives with 1 MB L2 cache, and that’s what this one is. If anything, this nicely illustrates that Intel’s product naming (Prescott/Nocona/Irwindale and so on) is rather arbitrary.
Note that CPU-Z thinks the CPU is an engineering sample (ES). It is not clear what that is based on; possibly simply the fact that a CPU with the exact characteristics is missing from CPU-Z’s database. The “Xeon” part comes from the board’s BIOS.
The latest version of Intel’s own CPU identification utility claims that the CPU was “made after the release of the utility” (droll sense of humor there!), in other words the utility has no clue.
According to Intel’s ark site, there were only three released processors with 3.73 GHz clock speed: Xeon 5080, Pentium Extreme Edition 965, and Pentium 4 Extreme Edition with HT. The first two are the same thing, a 65 nm dual-core Dempsey/Presler with 2 × 2 MB L2 cache. The 3.73 GHz P4 EE is a 90 nm Prescott, probably very very close to our mystery CPU. The difference is that the P4 EE has 2 MB L2 cache, and SL7HY only has one megabyte of L2 cache.
So what is the strange processor? Based on the available data, it looks like a variant of the Prescott Pentium 4 Extreme Edition with half the L2 cache. Possibly an unreleased precursor, given that the P4 EE was supposedly released in Q4 2004 and the SL7HY is from the end of Q2 2004.
Given how much heat it generates and how poorly it performs, the SL7HY CPU is not worth running, but it is interesting nonetheless.
Update: HWiNFO is just as confused by this processor as CPU-Z:
HWiNFO statement on SL7HY CPU
Yes, this is Intel’s own Bad Axe 2 motherboard. The board’s BIOS is where the Xeon designation is coming from.
And for good measure, the contents of /proc/cpuinfo from Linux:
processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Xeon(TM) CPU 3.73GHz stepping : 2 cpu MHz : 3733.467 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 1 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts nopl pni dtes64 monitor ds_cpl est cid cx16 xtpr bugs : bogomips : 7466.93 clflush size : 64 cache_alignment : 128 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Xeon(TM) CPU 3.73GHz stepping : 2 cpu MHz : 3733.467 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 1 apicid : 1 initial apicid : 1 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts nopl pni dtes64 monitor ds_cpl est cid cx16 xtpr bugs : bogomips : 7466.93 clflush size : 64 cache_alignment : 128 address sizes : 36 bits physical, 48 bits virtual power management:
Stuff like this is always neat. There were rumors of European dealers getting very small quantities of 4.0GHz Pentium 4 CPU’s as well that also never became official.
I’m skeptical that those were ever delivered. The CPU was definitely planned, and there’s even evidence in ark. Note how there’s no S-spec for that one. The CPU is also not listed on CPU-World which makes me strongly doubt that anyone has one (beyond an engineering sample perhaps).
Perhaps a special for an OEM? Every now and then I see Lenovo and Dell selling entire machines for slightly more than the retail price of the CPU it contains, so clearly the OEMs have some pull.
In the Netburst era AMD were still competitive with Dell and HP both shipping AMD machines. Perhaps it was Intel’s way wooing an OEM back?
What does HWiNFO report, out of curiosity? That tool actually will try to guess the qSpec…
Also, CPU-Z will use heuristics from the steppings, processor brand string, and such to figure out what’s actually going on. That’s where it’s getting the socket and the codename from, they’re not actually known in the CPU. So, the brand string is saying it’s a Xeon, the steppings match with a Nocona…
I have no direct experience with Intel CPUs, I do know that AMD had “OEM specials” with OEMs shipping CPUs that were not available through retail channels (or at least not until months later). So yeah, it’s entirely plausible that Intel did similar thing.
But… if they did that… where are those 4 GHz Pentium 4s? The CPUs wouldn’t just vanish. Given that there’s no evidence those CPUs were ever delivered, I’ll take it as a 99% solid proof that the rumor is just that, a rumor. The CPUs were planned but never materialized.
It would be interesting for me the output with linux of cat /proc/cpuinfo, I think that will be closer to the metal.
The 4GHz Pentium 4s never got the yields necessary to enter the mass market. I think small numbers were sold to specialty customers who needed the performance and were willing to pay an inflated price. The lower clock speed follow-ons with larger caches were faster for most users and lacked the yield problems. Unfortunately, with production totaling only in the thousands, the only way to get one would be to intercept retired systems on their way to the breakers.
Rumors are that Intel has a similar setup today selling small quantities of 5 GHz chips to deep pocket customers.
I noticed that the 65nm Pentium D was “losing” ~30W of TDP per new stepping at the same clock speed. I can imagine a 125W Pentium D 990 at 4.2Ghz based on the D0 stepping. I wonder if this was the original plan.
It’s just as confused as CPU-Z. See updated post.
That’s totally plausible, but what were these CPUs? Did they have some off-the-books S-spec? Or were they labeled as engineering samples? Did they also need a custom BIOS? Inquiring minds want to know…
Possibly. The problem I think was that such CPUs would have come out in the Core 2 era and would be horribly overpriced underperformers. I doubt such a CPU could keep up with, say, an X6800 Conroe (except in terms of heat dissipation).
The Xeon model string is coming out of the CPU itself. It isn’t the BIOS since it is a result of a CPUID instruction.
As for how the tools detect whether it is an engineering sample or not, it appears that it just based on having an internal database of expected values. There doesn’t appear to be any flag that indicates it is an ES CPU. cpu family: 15 model: 4 stepping: 2 doesn’t exist according to the various online lists. Stepping 1 is a Prescott. Stepping 3 is Irwindale, Nocona or Prescott again. Stepping 2 is your mystery CPU.
As mentioned by other people above, Intel do make weird CPUs as a custom order by somebody big. I have a couple E3 Xeons from eBay that were pulls from something but Intel doesn’t believe they exist at all.
Yea, I know it would not be as good as Conroe.
Did the extreme editions sell well? Could it be Intel’s way of getting rid of a bunch of unsold Extreme Editions? Somehow disable half the L2 and ship them out? I’m still leaning towards an OEM deal, but haven’t found any evidence for it yet. I suspect they must have wound up in consumer/big box retailer grade machines. That’s where I’ve seen all sorts of hard disk models that don’t officially exist and special (crippled) GPUs configurations.
The brand string may depend on a microcode update (that much is documented by Intel). Also, I don’t know if that’s true for Intels, but on AMDs the brand string is usually programmable and needs to be set by the BIOS.
I have personally seen the reported brand changing after a BIOS update for Intel CPUs (Core 2 IIRC). So it kind of is in the CPU itself and kind of isn’t.
This CPU actually has a stepping which is nowhere officially documented. There are no 0F42h CPUs in any of the Intel Specification Update PDFs (be it Pentium 4, Celeron or Xeon). There official Prescott 1Ms are: 0F33h (C0), 0F34h (D0), 0F41h (E0) and then 0F49h (G1). On the other hand, by searching for 0F42h I have found a site listing microcode updates with this stepping, so it Intel definitely supported them. I also would test it with a newer motherboard – the 875 did not support 1066 FSB, the 925 was the first to do it.
My guess is, this was one of the many OEM CPUs Intel released at that time. There were P4s which only made to OEM PC like Dell or HP – for example the Pentium 4 F-series, the first Pentium 4s with 64-bit enabled. I did a quick search for any news item mentioning Dell running a 3.73 GHz CPU, but couldn’t find anything, try it, maybe you will be more lucky.
This was a 975X chipset, not 875P. And the CPU did run with 1066 MHz FSB.
The theory about an OEM-only CPU sounds quite plausible, and would explain why it’s by all appearances a production processor yet “off the books”. A kind of semi-extreme edition, with faster FSB and clock but not the larger L2 cache. (Also a bit older than the 3.73 GHz P4 EE.)
As for the stepping… it looks that Celeron D 310, S-spec SL8S4, had that same 0F42h TFMS with G0 stepping. So that might be why it’s in a microcode update list. I can not find that S-spec in a specification update, but it is listed on ark (as G0 stepping). Weird!
How rare are ‘one-offs’ like this?
I wonder what its market value is among collectors?
How rare… that’s something most likely no one knows, because it’s completely unknown how many such CPUs were made.
As for market value, based on a sample of one, I’d say not higher than a “known” CPU of similar characteristics.
Since you can run linux on this CPU … Can you install the most recent Intel microcode update package? On the modern kernels the microcode gets updated the first thing, the moment the kernel loaded initrd. This update might let us identify the CPU better. Even if it does not, it can give us more info based on the fact the microcode revision has changed (or not).
and at the bios boot screen?
if not fully recognized by the bios a cpu may work-usually displayed as “xeon” or may not work PROPERLY:halting before going too far in the boot sequence.microcode in bios does not make ANY difference.
in windows the problem is simpler:any intel cpu can default to “xeon”….
well,show us THE BELLY of the processor-the little components will tell exactly what species is it in.
most important:why prescott was HOT?
because of factory over-voltage:stock 1.385V ??????? mine it’s been running for years at 1.100V-never gets over 50 celsius,it’s impossible;next cedar-mill do not go lower,either.
so,i think what you got is just a prescott-with stock 1.175V,big surprise….
I’ll take a photo or scan of the bottom when I find the CPU again.
The CPU as such is not precisely exotic. In terms of features, it’s extremely similar to generic Prescott and Nocona processors. It’s unusual in that it has a production S-spec that’s not documented, a CPUID signature (0F42h) that’s not documented, and it has an otherwise unknown combination of 1066 MHz FSB and 1MB L2 cache.
Hi,
I have a bit of a theory about what this is.
I think this was never a CPU Intel released in any way, even to an OEM. Based on what I’ve seen in the (two) images of this chip, and some CPU-Z validations, I believe the SL7HY to just be a re-lasered QDZA ES (which I also think is actually a Qualification Sample, not an Engineering Sample). There are several reasons for this:
– The lasering on both pictures of the SL7HY seems to be slightly off in the same places. This is most apparent in the E, I, and U of Pentium.
– The lot code is exactly the same in both pictures.
-The product string has (ES) in it, exactly the same as the QDZA. Even if this was an OEM CPU, a retail CPU would never report (ES) in the product string. There are many validations for the QDZA, so I don’t think it’s an issue of the board.
– The CPU is a 3.73GHz part – if someone were to find a few QDZA ES back in the day, it would be quite profitable to re-laser them and sell them as OEM parts.
If you would to sell or lend this CPU for testing, please let me know. Thank you.
Could both photos actually be of the same CPU?
I believe the OEM-only theory is more likely, because I can’t imagine why anyone would bother re-etching the label on the lid. That would imply selling just the CPU, but then the buyer would very likely see the ‘ES’ product string if they plugged it into a random board. Yet it the CPU were sold with a system with customized BIOS not showing ‘ES’, why bother with re-etching the CPU? It’s not like people routinely take off the CPU heatsink to check the S-spec.
On AMDs, the CPUID brand string is programmed by the BIOS (using a set of MSRs). The code is normally part of AGESA supplied by AMD. On Intel CPUs I believe the brand string is not programmable by software, but it is definitely affected by microcode updates. It is not burned into the CPU itself, not on AMDs and not on Intels.
The CPU is not currently for sale. I could run some tests on it if you tell me what exactly (and if I can dig up the CPU and board).
Hi,
The CPU in your picture seems a lot more worn than the other one, but I guess it could be the same, just well used? Without the unique code below the IHS, there’s really no way to know for sure.
CPU re-lasering is a fairly common scam. If you check eBay or Aliexpress closely, you can still find quite a few re-lasered CPUs. Unscrupulous sellers buy cheap and/or ES/QS chips and mark them into more profitable models. Even though the product string is different, they’d either sell to a buyer that will never check the product string, or if they do, by the time the buyer realises, the seller is long gone.
From what I know, the CPU product string is a permanent part of the CPU, but it can be changed. I can’t say much, but there has been some investigation into it and it is theoretically possible. Microcode may alter the way the chip is reported in certain places, though.
Speaking of microcode, I had a quick check of the Bad Axe 2 BIOS and I couldn’t find the 0F42 microcode. There has been at least one example of a Prescott chip with this CPUID (SL8S4), and I was able to find this microcode in the v1010.001 beta BIOS of the Asus P4P800-E. Maybe if this microcode is injected into another 775 motherboard (the Bad Axe 2 BIOS isn’t moddable, so you’d be better off finding an Asus or something) it will report itself differently.
Actually, I just remembered something.
A while ago, a user on a chat group posted about buying a 1151 CPU from a person who advertised it as an i3-7350K. When they tested it, it reported itself as “GenuineIntel 0000”, which is how modern engineering samples identify themselves. We were all excited for a new 1151 ES to be found, but it turned out that the user was running the CPU on a pre-Kaby Lake BIOS. After they updated it, it reported itself as a 7350K.
Perhaps that is what is happening with this CPU.
Yes, I have seen that kind of behavior with a Core 2 CPU. At first showing “GenuineIntel EM64T Processor” or something like that, after a BIOS update it was the right product string. That’s why I wouldn’t take it too seriously.
There is the related and curious case of the Core Duo T2600 which in some systems reports itself as “Genuine Intel(R) CPU T2600 @ 2.16GHz” (MacBook Pros and I believe others) and in others as “Intel(R) Core(TM) Duo CPU T2600 @ 2.16GHz”.
I’ll check what Asus etc. Socket 775 boards I have, it’s not a lot but I should have one or two.
I’d have an ASRock ConRoe865PE and Gigabyte GA-X38-DS4. I also have one or two additional Intel Socket 775 boards but those are probably uninteresting.
Is there any way to extract the microcode update from the BIOS and upload it with, say, Linux? That should actually work on any board…
I can’t find the F42 microcode in the BIOS of either board, but if you post on a forum like Win-Raid, someone should easily be able to inject it for you. I’m not sure how loading the microcode from Linux would work, sorry. I uploaded the F42 microcode here: https://drive .google .com/file/d/1T4htLrAewtfnyLCvdetNktVTFpC-jfYU/view?usp=sharing (remove spaces)
Please leave the link if you post on a forum. Thanks!
I can’t find the F42 microcode in the BIOS of either board, but if you post on a forum like CPU-World or Win-Raid, someone should easily be able to inject it for you. I’m not sure how loading the microcode from Linux would work, sorry. I extracted the microcode, but I think the spam filter automatically removes comments with links.
My handles are linuxfanatic and _haru on CPU-World and Win-Raid respectively. contact me if you make a post on either. Thanks!
Yeah, the link got flagged as spam, I un-spammed it. Thanks for the file!
I’ll check the microcode update and see how hard it might be to load it from Linux (I have no idea without doing some research first).
No problem. Let us know how you go, this is very interesting!
I also found an ASUS P5PE-VM board. Probably no different from the others?
Sorry for the late reply, from my brief check of a couple of BIOS versions the F42 microcode is still missing. No harm in trying to boot it, though.