Reusing old hardware - Wich matters more, CPU or RAM bandwith?

Hello. First message on the forum and its already a question , although I think this topic might be interesting to many people.

I'm upgrading an HTPC that it's currently running LibreELEC flawlessly, equipped with an Athlon X2 5200+ and 2 GB of RAM. For the complete picture, FullHD TV and mechanical hard drive (no 4K wanted/needed).

The reason for the upgrade is the motherboard, which is already showing its age. And some extra ooomph will be good, as I've already had some videos not working correctly (codec related, as transcoding those videos fixed the problem).

So, the main question is: which parameter is more important, CPU raw power/core count, or RAM bandwidth?

Right now I have two options for upgrading:
- Core 2 Quad + 4GB of DDR2. Plenty of raw power (2,66 Ghz), but RAM goes around 4GB/second.
- AMD Sempron 2650 + 4GB of DDR3. "Only" two cores at 1,45 Ghz, but RAM speeds to around 8GB/second. _{I wrote that before testing, and I used the theoretical speed. The real speed is 3GB/second...}

As I normally see the CPU doing not much when decoding video, I tend to think that it's better to have more RAM bandwidth, but I'm not really sure, that's why I'm asking.

Have a nice day, and thanks for the help

Thanks for the answer. Core 2 Quad then
I know this hardware is considered old, but it's working perfectly, and has plenty of power for what I need. Also, I got it free, as it's still old, but not still vintage (look for the price of a 486 PC on ebay ). And I can't bear trowing away nicely working hardware that it's still supported by the Linux kernel.

Best regards

I just tested the Sempron's RAM speed using the same test as the Core 2 Quad (Memtest X86 https://www.memtest.org/), and I've found that in spite of being 5 years newer, and using faster RAM, it's slower!! I know one is high-end and the other is low-end, but I wasn't expecting this... I've edited the first post to reflect that.