System Upgrade from Core 2 Duo to Core 2 quad / Core i3. Which is better?

go for i3. DDR3 is way more faster. actually you can sell your mobo n ram on ebay or amazon. n keep your expense low.

Well,i suggest you keep the motherboard and 4gb ram for other uses like making a htpc or a file server(which is very useful i must say).

Then get a H61 motherboard from Intel,Asus or Gigabyte(other brands shouldnt be trusted),and a Pentium G2010.It is more then enough to make the computer snappy again.However if you are so fussy that the GPU in the i3 goes to waste,why not get the i5 3350P?No gpu,but it is quad core instead of dual core which the celerons,i3 and pentium have.And twice the cache.It will be much better at multitasking.

Hoever,it seems your computer does not have an SSD!That is the most important thing to make a computer very snappy.therefore,my recommendation:

Get a Celeron G1610(still smokes all the Core 2 Duos,dont worry),a H61 motherboard from gigabyte(cheaper than asus,but asus is energy saving,so if you want to pay more for less bills asus is the way to go),and a 30-120GB ssd.Any brands is fine.Plextor M5S,Samsung 840,Kingston V series,Crucial M4,Crucial M500 are some i will recommend.

Note that the Celeron G1610 will not bottleneck the 550Ti at any time.

TheSSD usually comes with migration software which is easy to use.Make sure your hard drive data are on separate partition from the boot partition.then migrate the boot partition,delete the old boot partition through Right Click Computer then click Manage then go to something like Disk properties or something or is it some storage thinggy whatever.Finally extend the storage partition and change uefi settings to boot to the ssd first.

Also for ddr3 ram,get 1x4gb instead of 2x2gb if getting 4gb.if 2 gb ignore this.if 8gb then get 1x8gb not 2x4gb.

I had a similar situation figuring out what i should upgrade my Q6600 to. You didnt say how much the Q9550 cost but im going to assume its still not cheap. You would be totally wasting your money if you are just trying to keep your current board to *save* money, 775 is way out, even 1150 is on the way out, but atleast 1150 can support i7's if that time ever comes for you. If you upgrade to the 9550, that is it, you are stuck, you will 100% need a new board and ram after that, and the 9550 is already waaay outdated compared to i5s and i7s and the top of the line FX from amd. Back to the i3...the i3 actually edges out the core 2 quad 9950 in most tests, and wins significantly in others. Make the upgrade worthwhile and actually upgrade... Some of the i3's are not actually that cheap so you might as well spend the $50 more and get the i5. I understand you wanna keep your current system alive but its already going to be two socket models old.

Woah, don't listen to those guys saying take the i3. They just say that because they see i-something and want that. The Core 2 Quad has 4 cores. The i3 has two.

On a whim I also checked out the benchmarks at Toms Hardware. The Core 2 Quad wins every time.

If you're going to upgrade I'd go with the i3, new mobo and DDR33 RAM.

You're going to pay a lot for that Core 2 for such an old processor.

core 2quad extreme will out perform any i3 with current games, its all about caching and the use off, and you will have to get a new mobo and ram to go to the i range. If you are going to do that go for the i5 2700k, i still use a 2.4g q6600 not a big gamer but my gaming mates cannot believe how quick it is

thats better than others...

Option 2:

2. Core 2 quad 9550 without m/b and RAM

new tech vs old tech