Windows XP 32bit RAM priority?

[DerekC1990]

Hello, I'll be making a few references to this thread: http://www.techist.com/forums/f9/difference-between-32-bit-x86-64-bit-x64-171390/

Alright now onto the topic.
I recently installed Windows XP 32bit onto my new computer (home built). The system has 4gigabytes (2x2 gb) of DDR 1600 ram, and a Radeon HD 4870 1GB 256-bit GDDR5 PCI Express 2.0 x16 video/graphics card.

When I installed the system the Graphics Card was plugged into the motherboard as well as the 4 GB of RAM. Windows XP 32bit can only address up to 3.5gigabytes because 512megabytes are saved for other addresses and it simply can't read over 4gb of addresses.

My question is, is my computer reading 3.5gigabytes of on-board RAM or is it reading 2.5gigabytes of on-board RAM & the 1gigabyte on the video/graphics card?

If, due to installing with all the ram inserted, it is reading only the on-board RAM, is there a way to make it read the video/graphics card RAM? or do I need to do a fresh install of my OS with only 1 stick of RAM hooked into the motherboard during the initial install?

Thanks for any and all help.
Here is all the parts of my system in case anyone needs to see it:
Motherboard: Newegg.com - MSI NF980-G65 AM3 NVIDIA nForce 980a SLI HDMI ATX AMD Motherboard
CPU: Newegg.com - AMD Athlon II X4 640 Propus 3.0GHz 4 x 512KB L2 Cache Socket AM3 95W Quad-Core Desktop Processor ADX640WFGMBOX
Hard-Drive Primary: Newegg.com - Plextor PX-128M1S 2.5" 128GB SATA II Internal Solid State Drive (SSD)
Hard-Drive Secondary: Newegg.com - SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Video/Graphics Card: Newegg.com - ASUS EAH4870/2DI/1GD5 Radeon HD 4870 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card
ON-Board RAM: Newegg.com - A-DATA Gaming Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model AX3U1600GB2G9-2G
Power Supply Unit: Newegg.com - OCZ ModXStream Pro OCZ600MXSP 600W ATX12V V2.2 / EPS12V SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply compatible with core i7
DVD/CD Drive: Newegg.com - Sony Optiarc Black 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2MB Cache SATA CD/DVD Burner - CD / DVD Burners
Wireless Card: Newegg.com - EDIMAX EW-7128G IEEE 802.11b/g PCI Wireless Card Up to 54Mbps Wireless Data Rates 64/128-Bit WEP, 802.1x, WPA, AES
Monitor: Amazon.com: AOC 2436VW 24" Widescreen HD Monitor: Computer & Accessories
Keyboard:Amazon.com: Logitech Illuminated Ultrathin Keyboard with Backlighting: Electronics
Mouse: Amazon.com: Razer Naga MMOG Laser Gaming Mouse: Electronics

NOTE: I realize some of this is not necessary, but I wanted to give you as much background as possible in case it was important

 

[KSoD]

AFAIK, it is using all of the Video Card Memory and only 2.5GB of your system Memory. I will verify this and get back to you.