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Modifying the OG Xbox to have 256M of RAM [video]

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Re: Modifying the OG Xbox to have 256M of RAM [video]

#31

Post by userbinator »

kimixa wrote: post #7
Cieric wrote: post #4

Since it was mentioned in the Macho Nacho video, this was quite a hurdle. But it does bring up the question, what is the theoretical maximum possible? I know the CPU was 32-bit, so 4GiB is the upper limit in that regard. I don't know if the CPU has limited address lanes or any other physical limitation though. The max I've seen discussed is 1.5GB for a similar cpu on a normal desktop and 640MB for the test design of…

As the pentium 3 used the chipset for the memory controller, it's likely limited by that, though you'll likely struggle to find specs at that sort of level publicly available. Though assuming it's the same as contemporary consumer nForce chipsets may be a good assumption [0], which may be where the 1.5gb limit discussed came from. And the p3 also supported PAE [1], so technically could address more than 4gb of ram. T…

you'll likely struggle to find specs at that sort of level publicly available

Intel was far more open at that time (up through the Pentium IV era); here's the datasheet for the PIII:

https://download.intel.com/design/PentiumIII/datashts/245264...

...and yes, it does expose all 36 address bits on the FSB. The FSB protocol is actually the same as the one first used by the P6.

Re: Modifying the OG Xbox to have 256M of RAM [video]

#32

Post by [deleted] »

toast0 wrote: post #6
Cieric wrote: post #4

Since it was mentioned in the Macho Nacho video, this was quite a hurdle. But it does bring up the question, what is the theoretical maximum possible? I know the CPU was 32-bit, so 4GiB is the upper limit in that regard. I don't know if the CPU has limited address lanes or any other physical limitation though. The max I've seen discussed is 1.5GB for a similar cpu on a normal desktop and 640MB for the test design of…

I can't figure out if the xbox processor supports PAE or not. But references say most Intel processors after pentium pro, including Pentium III support PAE. Probably with 36 bits of physical addressing. But it's a mobile socket; no idea if they put all the address pins out on those.

[deleted]

Re: Modifying the OG Xbox to have 256M of RAM [video]

#33

Post by deaddodo »

laidoffamazon wrote: post #27
deaddodo wrote: post #14

Earlier quoted context omitted.

The Switch memory expansion is probably much more useful than this, for general users. No standing software is able to utilize this memory expansion, only homebrew software specifically coded for it can. In contrast, the Switch OS manages memory for apps and would be able to allocate additional memory automatically, as long as it's been made aware.

Also, if my YouTube recommended is any indication there's a healthy Linux ecosystem for the Switch and the X1 now - some people have even shown Switch games playing on Switch via emulator in Ubuntu [0] [0] https://youtu.be/H1gveQUBIKk?t=2332

That's because nVidia has always had a decent support level for their Tegra chips via the Jetson program, the X1 being one of the better utilized ones.

The Switch benefited greatly from that community.

Re: Modifying the OG Xbox to have 256M of RAM [video]

#34

Post by Arrath »

jsheard wrote: post #11
Dwedit wrote: post #5

The real question is if this will stop Morrowind from secretly rebooting the XBOX at certain load screens.

Probably not, at least not without hacking the game. Typically only things which were built to use the extra RAM see any benefit, whether that's homebrew, leaked game betas which rely on the extra RAM that devkits had, or games made for the Sega Chihiro arcade platform which was basically an Xbox but with double the RAM.

There was a great article here a few months ago on this very subject, detailing getting Halo 2 to run in true HD, properly using the extra RAM of the devkit, and the engine hacks required to do so (since it basically statically allocated a handful of regions and couldn't dynamically go "oh look more RAM!"). It was a good read!

Re: Modifying the OG Xbox to have 256M of RAM [video]

#35

Post by trentnelson »

LukeShu wrote: post #30
Rinzler89 wrote: post #15

Earlier quoted context omitted.

>It's wild to think that Intel was looking at 4GB and saying, "This probably isn't going to be enough." Not really. While consumers at home had 8MB, Intel was already looking to compete with PowerPC, DEC Alpha, MIPS systems where 4GB wasn't really out of the ordinary, so they knew where things were going.

As far as I know, there were only 5 PPro computers that could take >4GB: Axil Northbridge NX801, Data General AV8600, HP NetServer LXr Pro8, NCR Worldmark 4380, or Unisys XR/6 Interestingly, while the Intel 450GX chipset was designed to daisy-chain DRAM controllers (1 controller chip per 4GB of RAM), none of the boards that actually could take >4GB used that, instead building their own solutions. Presumably that mean…

Had fun googling those system names. NX801: https://www.tpc.org/results/individual_results/axil/axil.nx8...

200 9.1GB SCSI disks for 1.8TB!

And still only 4GB RAM on that SQL Server 6.5 box they used for TPC-C. Wild.

And yeah, $770k for that server.

Edit: I guess whilst I'm at it...

Data General AV8600: https://www.tpc.org/results/individual_results/dg/dg.8600.es...

HP NetServer LXr Pro8: https://www.1000bit.it/ad/bro/hp/netserverlxrpor8.pdf

Re: Modifying the OG Xbox to have 256M of RAM [video]

#36

Post by LeFantome »

wk_end wrote: post #13
toast0 wrote: post #6

Earlier quoted context omitted.

I can't figure out if the xbox processor supports PAE or not. But references say most Intel processors after pentium pro, including Pentium III support PAE. Probably with 36 bits of physical addressing. But it's a mobile socket; no idea if they put all the address pins out on those.

OT: Like you mentioned PAE was introduced with the Pentium Pro in '95. That was the same year my family got its first PC, with a whopping 8MB of RAM. It's wild to think that Intel was looking at 4GB and saying, "This probably isn't going to be enough."

Where I worked back in 1995, we had DEC Alpha workstations running Windows NT processing what were then huge images. We had DEC workstations running 4 GB of RAM.

I think some Alpha systems had 8 GB installed even back then.

The Alpha was 64 bit native but Windows NT was still 32 bit so I think you needed VMS if you wanted more than 4 GB. A 64 bit version of Windows 2000 for Alpha was created but never released ( this was the first 64 bit Windows ).

It was not totally impossible to see beyond 4 GB of RAM.

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