For dual-channel you need two (with preferably same number of ranks/banks) memory sticks. Same batch is not needed.
More memory stick (above 2) will not give you additional performance gain.
Memory configuration depends on "where" you will put those 2 sticks - on the same channel, or separate.
Moreover some motherboards supports so called "asymmetric" dual-channel - with sticks of different size (i.e. 2GB and 1GB), but I suppose it will be less optimal than normal dual-channel (aka "symmetric").

Four memory sticks will only be needed for quad-channel memory configuration 😀

Thank you. I will stay with 2 x 2GB sticks then for dual channel.

Its intel branded board therefore you wont get any options for overclocking/customizing timings. Dont worry about ram too much, its at best ~5% difference in games.

OS does not care what capacity of motherboard if not supported fully, for example 32bit XP. The bandwidth changes either way when populated one or two slots or even four. Putting in dual or more channel mode helps with igpu the most and some improvements when using a GPU.

There is exceptions, if motherboard cachable range is limited, keep memory size up to this limit. And another is OS limitations like 98 and 98SE as well as 95 causes instabilities if max memory is exceeded.

Cheers,

zyga64 wrote on 2023-06-16, 10:21:

Four memory sticks will only be needed for quad-channel memory configuration 😀

That's not true. Memory controller can also do bank interleaving, which is on per channel basis. So for typical dual channel motherboard configuration you need two dual-rank or four single-rank sticks to achieve optimal performance.

The Serpent Rider wrote on 2023-06-16, 23:39:

That's not true. Memory controller can also do bank interleaving, which is on per channel basis. So for typical dual channel motherboard configuration you need two dual-rank or four single-rank sticks to achieve optimal performance.

Small thing to add :
LGA 775 chipsets may experience lower OC headroom when fully populated with 4 DIMMs of Dual Rank configuration.
Not that important in this case (since OC is quite limited on Intel board), but might be in someone else's case.

The Serpent Rider wrote on 2023-06-16, 23:39:

zyga64 wrote on 2023-06-16, 10:21:

Four memory sticks will only be needed for quad-channel memory configuration 😀

That's not true. Memory controller can also do bank interleaving, which is on per channel basis. So for typical dual channel motherboard configuration you need two dual-rank or four single-rank sticks to achieve optimal performance.

Thank you ! I didn't know that.

zyga64 wrote on 2023-06-17, 12:51:

The Serpent Rider wrote on 2023-06-16, 23:39:

zyga64 wrote on 2023-06-16, 10:21:

Four memory sticks will only be needed for quad-channel memory configuration 😀

That's not true. Memory controller can also do bank interleaving, which is on per channel basis. So for typical dual channel motherboard configuration you need two dual-rank or four single-rank sticks to achieve optimal performance.

Thank you ! I didn't know that.

Thanks for clarifying!

Cheers,