I agree the System X uEFI legacy implementation is so painfully slow, that I might even avoid selling them as a platform to my clients.
Measuring the IBM form the time it starts a legacy USB key boot until I get an OS prompt is ridiculously long. I am using SmartOS (an illumos/opensolaris derivative for all intents an purposes once booted it runs and acts a lot like Solaris 11) which acts like puppy Linux e.g. it loads a 275MB "compressed" blob (the entire OS) and then boots the OS in memory. This really showcases the problem with IBMs uEFI implementation of legacy booting.
BEG: 1:27:05 pm (start SmartOS USB 2.0 USB key)
END: 1:33:38 pm (done into running SmartOS - we read 275MB)
TOOK: 6:33 (six minutes and 33 seconds - pretty slow - only 0.75MB/sec.)
It is almost as if the UEFI implementation uses a tiny block size like 512 byte reads, rather than a larger buffer during reads. Once I am in the OS I can benchmark the performance of the USB key I booted off, IMHO if the IBM UEFI code would just read a 8192 block size or better yet a 32768 block size the resulting boot would be super fast.
So once in a SmartOS operating systems I saw the following performance characteristics for my USB key, ranging form 512 byte to 131072 bytes. Looks like either 8192 block size (12.3 MB/sec in a booted OS) or better yet a 32768 block size (20.2 MB/sec in a booted OS) would be good choices. It also looks like a 512 block size (0.64 MB/sec in a booted OS) matches pretty close the results I seem to experience in my lengthy boots.
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=512 count=524288
524288+0 records in
524288+0 records out
=> 00.64MB/sec. on SmartOS like Solaris 11 (this is the speed of the IBM bios boot speed)
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=1024 count=262144
262144+0 records in
262144+0 records out
=> 02.56MB/sec. SmartOS like Solaris 11
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=2048 count=131072
131072+0 records in
131072+0 records out
=> 05.09MB/sec. SmartOS like Solaris 11
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=4096 count=65536
65536+0 records in
65536+0 records out
=> 07.74MB/sec. SmartOS like Solaris 11
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=8192 count=32768
32768+0 records in
32768+0 records out
=> 12.33MB/sec. SmartOS like Solaris 11
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=32768 count=8192
8192+0 records in
8192+0 records out
=> 20.02MB/sec. on SmartOS like Solaris 11 (as expeected and seen on a Win7 box)
time dd if=/dev/dsk/c1t0d0p0 of=/dev/null bs=131072 count=2048
2048+0 records in
2048+0 records out
=> 22.19MB/sec. SmartOS like Solaris 11
I was using the following a new IBM x3550 M3 with UEFI (BIOS) rev 1.13 (12GB ram, and one 2.266GHz Xenon processor)
Firmware Type Version String Release Date
IMM YUOOC7E 09/30/2011
UEFI D6E154A 09/23/2011
DSA DSYT89P 10/28/2011
I must say I am sorely dissapointed with the "speed" of USB booting in the legacy BIOS mode in the IBM UEFI implementation.
Food for thought for my 275MB image a Supermicro XSCA9F or an Oracle-Sun X4275 will boot a 275 MB usb key image in just 32 or 33 seconds respectively, while the IBM x3550 M3 takes over 363 seconds for the same image (11 times slower).
This performance is totally unacceptable and the issue exists across the entire System X line. I have been in contact with IBM and they just say try a uEFI boot load (which is like saying to me learn the UEFI spec, learn GRUB2 and write your own custom boot loader, yes its doable but I don't have an extra 2-3 weeks to mess with this stuff). Yes using a "pure" uEFI boot should work fast but I can not prove it, however then I couldn't used "standard distros" and also as I indicated I would be forced to write my own uEFI boot loader.
This problem "slow legacy booting" was reported by me under IBM Problem/Ticket # A02PGGK, I even tried contacted the uEFI developer (I think it is Michael Brinkman) directly, however IBM doesn't seem like they care to acknowledge this issue and the large community of people and companies that are impacted.
I have also posted a similar anaysis to a thread at http://communities.intel.com/thread/3909?wapkw=uEFI which also discusses "slow booting" back in Sep. 2009 here it is the same issue I have been seeing
Boot time is too slow. It take about 20 minutes to boot a VMware ESX
when EFI is used, compared to less than 2 minutes with the normal bios
this is the same 10X or 11X slowdown I experience, hopefully some day IBM will fix this.