Abit IP35 Overclocking advice

Hi,

I currently have the following setup:

Abit IP35 Dark Raider
Intel Core 2 4400 2.0ghz proc
DDR2 2GB (2X1GB) 5300 667
Nvidia 8800 GTS OC2

I am looking to overclock the processor to 266fsb/2.66ghz. When I change the FSB to 266 the memory speed changes to ddr2-886 on default. When on default fsb 204 the ddr2 is 680.

I can change the memory settings and have the following options:

1:1.00 DDR2 532
1:1.2.00 DDR2 638
1:1.25 DDR2 666
1:1.50 DDR2 798
1:1.66 DDR2 886
1:2.00 DDR2 1064

Can anyone advise what settings I should choose. 1.1.25 ddr2 666 results in failure to boot and I have to clear CMOS. Am presuming if the ratio is currently 3:5 then i should choose 1:1.66 for ddr2 886 however thats over my memory speed so dont want to do anything when im not sure...

CPUZ brings up the following more detailed information:

CPU-Z 1.41 report file

Processor(s)

Number of processors 1
Number of cores 2 per processor
Number of threads 2 (max 2) per processor
Name Intel Core 2 Duo E4400
Code Name Conroe
Specification Intel(R) Core(TM)2 CPU 4400 @ 2.00GHz
Package Socket 775 LGA
Family/Model/Stepping 6.F.2
Extended Family/Model 6.F
Core Stepping L2
Technology 65 nm
Core Speed 1224.2 MHz
Multiplier x Bus speed 6.0 x 204.0 MHz
Rated Bus speed 816.1 MHz
Stock frequency 2000 MHz
Instruction sets MMX, SSE, SSE2, SSE3, SSSE3, EM64T
L1 Data cache (per processor) 2 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache (per processor) 2 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache (per processor) 2048 KBytes, 8-way set associative, 64-byte line size

Chipset & Memory

Northbridge Intel P35/G33/G31 rev. A2
Southbridge Intel 82801IR (ICH9R) rev. 02
Graphic Interface PCI-Express
PCI-E Link Width x16
PCI-E Max Link Width x16
Memory Type DDR2
Memory Size 2048 MBytes
Memory Frequency 340.0 MHz (3:5)
CAS# Latency (tCL) 5.0 clocks
RAS# to CAS# (tRCD) 5 clocks
RAS# Precharge (tRP) 5 clocks
Cycle Time (tRAS) 15 clocks
Command Rate (CR) 2T