In boot.ini you can add /3G to your nt loader options similar to below

;
;Warning: Boot.ini is used on Windows XP and earlier operating systems.
;Warning: Use BCDEDIT.exe to modify Windows Vista boot options.
;
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows XP" /NOEXECUTE=OPTIN 
/FASTDETECT /3G


-- 
Regards,
- Umut Alev [MSFT]

This email sent from a machine running Vista RC1.


"Vivek" <vivekd@o...> wrote in message 
news:44f9829d$0$11968$afc38c87@n......
> Hi,
>
> I am using x86, 4GB physical memory. What is the /3G flag? Can you please 
> clarify that? Thanks...
>
> Yes, it is the same issue, they are related I have just realised.
>
>
> Regards,
>
> Vivek
>
>
> Umut Alev - MSFT wrote:
>> Yes you would see some trashing and eventually you would start getting 
>> E_OUTOFMEMORY.
>>
>> Are you running under x86 or x64? Usually x86 can only see upto 2GB after
>> that you need to turn on /3G flag. To access full 4GB you need to switch 
>> to x64.
>>
>> I have read your get_xml question. Is this the same issue?
>>