hello, bought 8gb of 800 mhz ddr2 ram for the mac pro to install. I placed all 4 of the big ram (2gb in the top tray) I put the 2 1gb ram modules in the bottom tray as that was the recommended set up. Sadly my mac shows only 6 gb of ram are being recognised. Any ideas? ---------- it recognises the two 1gb modules in the bottom tray (b) DIMM 1 & 2 It recognised the two 2GB modules in top tray (a) DIMM 1 & 2 It says that DIMM 3& 4 in the top (a) tray are not installed... but they are! ---------- ok I put the 2 2gb ram that was in DIMM 3 & 4 in the A tray into the DIMM 1&2 in the B tray. I them put the 1gb modules into the DIMM 3&4 in the bottom (b) tray. It now recognises all the ram. Can anyone confirm this is the optimal way to use the ram?