SSD recommendations for older system

Sandisk Extreme is good, as it uses toggle mode NAND. Personally, I care more about longevity than the minor performance difference between SSDs, and being based on a Sandforce controller the Sandisk will at least be in the category of low write-amplification, however it uses smaller lithography process NANDs. You're not really likely to find older 32-35nm NAND chips around anymore anyways though.

The Sandisk uses a lot higher density NAND dies than many other SSDs, so lower capacity models like the 120GB have less parallel channels compared to competing toggle-mode NAND such as the Mushkin Chronos Deluxe or the OCZ Vertex 3 MAX IOPS, but the 240GB model shouldn't bottleneck you there.

Therefore, if you too prefer low-write amplification vs better performance on uncompressable data, the Sandisk Extreme 240GB is a fine choice.

Pretty much every motherboard that doesn't have native SATA III ports, also only has PCI Express 1.0 x1 ports. However, Most add in cards will support PCI-E 2.0 and if you put it in a spare x16 slot, you'll likely get 500MB/s vs 250MB/s from the x1 slots, or 300MB/s from a native SATA port. Additionally, there are many PCI-E x4 cards (actually x2 electrically) that you can get that will have a peak theoretical bandwith of 1000MB/s in a 2.0 slot, and should therefore not bottleneck you compared to a native SATA III port.

Most people however, do not have multiple PCI-E x16 slots on their motherboard, and are limited to only x1 slots that operate at PCI-E 1.0 speeds, and therefore will almost always get faster speeds on their SATA II 3.0Gbps ports than an addon board with 6.0Gbps, but you have more flexability with that P5Q Deluxe

After a couple hours of research earlier I chose two Sandisk Extreme 240GBs for myself (2 separate PCs). Seemed like a fair choice, and the 160 price tag (on sale) made it an easy decision.

Thanks for the input. The Sandisk drive does look good.

Since I do have extra PCI-E x16 slots on my MB, maybe I'll go with an add on card after all. Looking around at what Fry's has, I see SATA III cards that say they are compliant with PCI-E 2.0, but is that all it needs? They say "compliant with 2.0 but backward compatible with 1.x", but they also say they are PCI-Express x1 cards. Such as the Syba SY-PEX40030. That's not going to do it, is it?

Thanks.

A PCI Express x1 2.0 card running at 2.0 speeds should give you 500MB/s bus bandwidth, which should outperform a native SATA 3gbps link in throughput.

The PCI Express x1 2.0 cards I've seen use a Marvell controller. I've read using the SATA 3gbps on the MB with the Intel controller will be better performance than the SATA 6gbps on a card with a Marvell controller. Any idea if this is true?