Hi uggla
You could take a look at the output of  dmesg  and see if maybe your hard drive is being put
into PIO instead of DMA mode.
Rich,
Am using code you suggested on the forum.    Good thinking  
 
   Along the lines of this thread,     Have been making timed bootups, listed below.
HP motherboard, 2.8 GHz speed, 1 GB RAM. 
Booting from a USB pendrive, partitioned EXT2 and VFAT32. 
Have TCL installed in USB sdb1,         with /tce on sdb1 and sdb2.
sdb1 is EXT1,     sdb2 is vFAT (of course /tce is internally formated to EXT2).
Found that it is necessary to use the UUID, 
otherwise TCL will scan for Hard-Drive installation of /tce (and if there WILL find and LOAD it). 
On USB bootup, 
Select bootcode (1) in order to load  sdb1/tce  
Select bootcode (2) in order to load  sdb2/tce  
Then,   start the clock ! 
(1)
title =1={ TINY-CORE : Rich-TCL ( loads sda1/tce/optional/apps.tcz  \n (find(MARK)-kernal(uuid)-initd)
   find --set-root --ignore-floppies --ignore-cd  /LG-MARK
   kernel  /tc-sys/bzImage  psubdir=/tc-sys  quiet  waitusb=10:UUID="074e2d15-9ac0-4466-8d4c-9650d908c101" tce=UUID="074e2d15-9ac0-4466-8d4c-9650d908c101"
   initrd  /tc-sys/tinycore.gz
(2)
title =2={ TINY-CORE : Rich-TCL ( loads sda2/tce/optional/apps.tcz  \n (find(MARK)-kernal(uuid)-initd)
   find --set-root --ignore-floppies --ignore-cd  /LG-MARK
   kernel  /tc-sys/bzImage  psubdir=/tc-sys  quiet  waitusb=10:UUID="074e2d15-9ac0-4466-8d4c-9650d908c101" tce=UUID="07DB-A20C" TYPE="vfat"
   initrd  /tc-sys/tinycore.gz
Table of results:
------------------------------------------------------------------------------------
SDB. . . ColorBg. . .Read-USB. . .Load-RAM. . .Load-Ext. . .Exit-Save. . .
.1          Yellow             30s              4s               1              80s
.2          Purple             30s              4s               1               1s 
-----------------------------------------------------------------------------------
No complaints, just noting times, along the lines of this thread.
Your bootcode was researched as best as I can.   
TCL Docs are terse. 
grub4dos docs are not complete. 
jackson.lee