First of all, the motherboad manual will tell you what slots do what and if they are color coded, I would say you are screwed up right now because they color code them for a reason. Also, some have 2 high speed slots and 2 slow speed... again, this is specific to the motherboard and the manual will tell you what happens with the sticks installed

as for the FSX demo, bad way to judge FSX

The demo sucks compared to the final SP2 product

dual-channel,  either yellow yellow or black black
go in to the bios and set the speed your memory is rated at if not ocing.........jumper free/chip

It should be unplug/plug, power up, boot, verify, change settings if needed... F10 and go

The BIOS is not going to change in the timing area. All you are doing is swapping the port, however, always switch off the PSU, unplug the tower from the wall and always hit the power button 2-3 times to discharge the system before making such a switch. I do not see anything that would go wrong from a typical electronics point of view unless the PB5 was know for some type of screwy response to such a change. I personally have never see any issues from moving things around and you do need to go into the BIOS and confirm the stick is recognized and the settings are correct. Some BIOS have a separate 'mode' setting for dual channel operation which you may need to enable

I do not know the board or its BIOS so I can not advise directly about it, only generally.

I'm running a P5B (Deluxe)

I remember reading that some others were also confused about what the manual stated about RAM placement on the P5B series.

Anyway, you are correct about using the color coded RAM slots as a guide for dual channel.
I don't have my manual handy but, I'm using the two yellow channels (1&3 I believe) and my start up screen conferms that it's (2x1gig) running dual channel. You can also use channels 2&4 for dual channel.

If you have 4 RAM sticks, you can use all four channels and it will run dual channel.

Just move one of your RAM the sticks to a different slot and it will be running in dual channel mode, no BIOS cofiguration needed on the P5B

download a little utility called CPU-Z, run it and select the 'Memory' tab, it will tell you (in the upper left corner) if the motherboard is using single or dual channel.

I know some mother boards seperate the memory channel by colour, for instance blue is channel 1 and green is channel 2, so you would plug one stick in blue and the other in green, but then some motherboards get the hump if you use slot 1 instead of slot 2 etc etc. Main thing here is experimentation, dont worry you wont do any harm to the pc, it will simply not boot up or make a long beeping noise.

But first try that utility i gave you the link for. Oh and before you touch pc components just ground yourself on to a tap or radiator or something.

What is the memory product being used?

Is it Gskill?

http://www.xtremesystems.org/forums/showthread.php?t=116029

http://www.xtremesystems.org/forums/showthread.php?t=109379



According to OCZ this is not limited to Gskill. They also had problems

http://www.bleedinedge.com/forum/showthread.php?p=191541


And it was stated BIOS releases helped but the bottom line was some had to still enter the BIOS and set things up manually, which means you need to know the fab-4 timing of the memory and the voltage they are designed to run, and set CAS X-X-X  TRAS X   and the voltage up manually, then F-10 save and exit... shut down install the stick(s) and boot.


Tony, head engineer at OCZ, laid out setting up a PB5 here: http://www.thetechrepository.com/showthread.php?t=41

I would check and see what BIOS is the most recent and see if you are behind in that area. The current BIOS revision being run can be see in CPUz

0302
P5B Deluxe Release BIOS version 0302
Initial Release


0405
P5B Deluxe Release BIOS version 0405
1 .Add auto calculate DDR frequency rule to display DRAM frequency
2.Support FSB533 CPU over 3.4GHz frequency under AIBooster.
3. Support max FSB from 400MHz to 500MHz
4. Fix AIGear may sometimes show fan speed too low sometimes under normal mode
5. Revise EIST module


0507
P5B Deluxe Release BIOS version 0507
1. Support Conroe CPU ratio adjustment
2. Fix some DDR 800 frequency will show DDR 533                                  <---------------------------------------------
3. Enhance performance when using NVDIA 7950GX2 VGA card
4. Fix fail to read files from some ODDs
5. Fix "Hit 'DEL' message display" item function fail
6. Support Max FSB from 500 MHz to 650 MHz


0614
P5B Deluxe Release BIOS version 0614
1. Support DDR2 double side x16 module <---------------------------------------------
2. Enable support for CPU ratio adjustment on Kentsfield B0 stepping CPU
3. Enable conroe/kentsfield ratio overclocking higher above default value
4. Fix CPU Fan profile mode not correct after system shotdown
5. Enhance memory compatibility for DDR533 and DDR667 modules. <---------------------------------------------
6. Revise S3 fuction not stable when CPU FSB over 300MHz.
7. Enable support for OCZ2G8002GK-6400                                             <---------------------------------------------
8. Fix PCIEX1 will disappear after update beta bios from 0405 to 0507
9. Fix some lock cpu will show "modify ratio "item in bios(ex:660-SL7Z3 3.6GHT PSC800 2M/EM64T 002)
10. Fix some lock cpu frequency not correct when lock free fuction enable(ex:660-SL7Z3 3.6GHT PSC800 2M/EM64T 002)
11. Fix kentsfield L2 cache not correct issue (in bios setup)
12. Fix SATA configuration select disable and compatible mode, and BIOS still show SATA5 and SATA6
13. Update ICH8 Raid option ROM from V6.0.0.1022 to V6.1.0.1002
14. Update Marvell 8001 and 8056 Lan option rom from 5.16.3.3 to 5.17.1.3


0701
P5B Deluxe Beta BIOS version 0701
1. Fix chassis fan2 may not detect fan speed under ProbII if low spin fan is used. 


0706
P5B Deluxe Beta BIOS version 0706
1 Enhance CrossFire performance.
2 Enable NVIDIA 7950GX2 display under crashfree mode
3 Fix CPU frequency not correct when use ES CPU and lock free fuction enable
4 Fix memory display message not correct under multi-language
5 Add Kentsfield B3 uCode 


0711
P5B Deluxe Release BIOS version 0711
1. Fix DRAM frequency incorrectly display problem under auto, standard and AI N.O.S mode <---------------------------------------------
2. Add check ATI CrossFire VGA card routine
3. Add ASUS Cross Graphics Impeller (ASUS C.G.I) feature
4. Reduce system full reset of times
5. Patch some VGA card can't found when NB Vcore value has been set too high
6. Fix DDR frequency 889 unstable by SPD                                                               <---------------------------------------------   here is a big one
7. Enable support for NVIDIA 7950GX2 cards under recovery mode
8. Fix CPU frequency not correct when use ES CPU and lock free fuction enable
9. Fix memory display message not correct under multi-language
10. Add new CPU Ucode to support Kentsfield B3 stepping CPU
11. Fix chassis fan 2 speed not correct when fan speed too low
12. Fix ATI CrossFire can't work when using with 800FSB Prescott CPU
13. Enhance Chassis Q-Fan sensitivity
14. Improve memory compatibility

** Please perform CMOS clear after update to this BIOS.


0804
P5B Deluxe Release BIOS version 0804
1. Support conroe L processor
2. Update JMicron option rom 1.06.22
3. Modify CPU fan low limit speed from 800 RPM to 600 RPM
4. Implement ASUS CGI performance with ATI 1950 graphic cards


0910
P5B Deluxe release BIOS 0910
1. Update Jmicron option ROM to 1.06.59
2. Fix AC Power loss function not correct
3. Support x4 DIMM                                            <---------------------------------------------  another big one
4. Moidfy Write to Precharge Delay default from 10 to 11
5. Enable support for EIST under VISTA
6. Finetune Q-Fan rule
7. Support SLP 2.0
8. Fix BBS device string not correct under AHCI mode
9. Enable Disable USB capability
10.Support ASUS WIFI-TV card
11.Revise CPU temperature calculation algorithm for PECI


1004
P5B Deluxe Release BIOS 1004
**Please update AsusUpdate to V7.09.02 or later prior making this update.**
**This BIOS does not support roll back to older BIOS**
1 Enhance memory compatibility
2 Support CONROE E0 CPU(FSB 1333)


1101
P5B Deluxe Release BIOS 1101
1 Add new uCode to support new CPU.
2 Fix system won''t complete POST with GV-MVP/RZ2(TV tuner) connected and power on before motherboard.


1212
P5B Deluxe BIOS version 1212
1. Add new CPU uCode to support new processors
2. Revise SLP 2.0 rule
3. Enable support for SATA hot plug function under AHCI mode
4. Fix after downgrade CPU ratio, the Conroe L frequency not correct under ASUSCPU


1215
P5B Deluxe BIOS version 1215
1. Enhance memory compatibility under FSB1333 mode                                     <---------------------------------------------



1216
P5B Deluxe BIOS version 1216
1. Finetune CPU temperature detection algorithm


1219
P5B Deluxe BIOS version 1219
1. Support new CPUs. Please refer to our website at: http://support.asus.com/cpusupport/cpusupport.aspx
2. Finetune CPU Voltage Low Limit
3. Finetune Q''Fan control code for chassis Q''Fan


1221   
P5B Deluxe BIOS version 1221
1. Support new CPUs.


1223
P5B Deluxe BIOS version 1223
1. Fix FSB speed issue after adjusting CPU ratio


1226
P5B Deluxe BIOS 1226
1. Fix CPU ratio will not reset after load BIOS default
2. Enable support for N/2 Ratio option





The latest BIOS is dated 11/30/2007 and it is BIOS # 1226

I can not vouch for anything with this board. All I can do is relay what I remember and what I see.

I do remember I passed over this board because in my opinion, even though it had a rep for being a clockers toy,  it was buggy and from the following list of BIOS releases in which the number of releases and type of fixes are unusually high, you see what I mean.


That board requires an updated version of ASUS's flash utility. That can get tricky and I would have to research it to find out whats going on in that area but if you do not use the right utility you could end up with a dead board, and Asus does warn that once you flash BIOS 1004 or above you can not go back
P5B Deluxe Release BIOS 1004
**Please update AsusUpdate to V7.09.02 or later prior making this update.**
**This BIOS does not support roll back to older BIOS**


There are things I would need to look into prior to suggesting a flash but the bottom line is based on what I see and your problem, I bet the BIOS on that system is old and needs to be updated, badly. Is that going to magically fix things? Perhaps, but it may also require you set those sticks up correctly in the BIOS manually which is why I posted the Gskill numbers from extreme systems running on a P5B.