I didn't find the P4 2.6, but tom's charts have something similar:
3DMark06 - CPU
Version 1.1 (1280x1024 @ 32 bit)
Intel Pentium 4 "E" 520
Prescott,2800/200,P35,533,Socket 775,12K?Ops+16 kB,1 MB
Score:
846
Intel Pentium D 920
Presler,2800/200,P35,667,Socket 775,12K?Ops+16kB,2 MB
Score:
1244
Intel Pentium Dual Core E2140
Conroe L,1600/200,P35,800,Socket 775,32+32kB,1 MB
Score:
1393
Intel Core 2 Duo E4300
Allendale,1800/200,P35,800,Socket 775,32+32kB,2 MB
Score:
1579
AMD Athlon 64 X2 4800+ EE (G1)
Brisbane (65nm),2500/200,NF590,714,Socket AM2,2x 64+64KB,512 KB
Score:
1843
You do mean $50-$60 each, right? If that's the case, I would suggest this combo. I know it's not intel, and the motherboard is a little more expensive, but at this level of price ($120-$150.00), it seems to be a great deal.
http://www.newegg.com/Product/Product.a ... 6819103212
http://www.newegg.com/Product/Product.a ... 6813128090