On Fri, 3 Dec 1999 20:58:24 -0500 (EST) 
Jason R. Thorpe <thorpej@nas.nasa.gov> wrote:

> ...well, the XLs are slow, too :-)  They're roughly equivalent to the
> AlphaStation 400;

While this is true for the XL233 and XL266 (slowness), this is
not the case for the XLT300, XLT366 and XLT433 machines.

The XL233:

 - CPU: DECchip 21064A @ 233Mhz (EV45) with 16KB instruction
   cache & 16KB data cache;
 - Secondary cache: 512KB direct-mapped/writeback;
 - Core Logic: DECchip 21071-AA chipset provides memory and
   cache control, and a bridge to the PCI bus;
 - Memory Interface: 64-bit, 33-bit ECC.;
 - Console Firmware: 512KB flashrom containing ARC firmware.

SpecINT95: 4.3, SpecFP95: 5.7 
 
(The XL266 is the same; except the cpu runs @ 266Mhz and it 
 sports 2MB second level cache).

The XLT366:

 - CPU: DECchip 21164A CPU @ 366Mhz (EV5) with 8KB instruction
   cache, 8KB data cache and 96KB on-chip secondary cache;
 - External cache: 2MB Bcache (direct-mapped, writeback, ECC);
 - Core Logic: DEC Semiconductor 21172 chipset, provides memory 
   control, data paths between memory and CPU, and a bridge to
   the PCI bus;
 - Memory Interface: 128-bit*, 36-bit ECC (*256-bit if all banks
filled);
 - Console Firmware: 512KB flashrom containing AlphaBIOS firmware.

SpecINT95: 11.3, SpecFP95: 16.2

As you can see, the XLT366 is about 3 times faster than an XL266
(the XLT300 and XLT433 are the same, only different CPU speeds).

The XL and XLT's mainboards and cpu-riser cards are also not
compatible with each other; hope this clarifies some things ;-)

Now let's hope that Compaq will release SRM firmware for the
XLT too (since I own 2 of them).

-- 
Best regards,
Antoine