Does your pan have a lid? That can make a big difference. You need a lid.

I just did some indoor tests, in close to ideal circumstances (no wind etc, although I had a door open for ventilation). 500ml of water, small Esbit-style stove, in a pan with a lid at 150ft above sea level. The genuine Esbit fuel took about 6 minutes to boil. (The temperature measured over 99C).

My preferred fuel is the army stuff which is flat, squarish waxy blocks about 1.75" wide. I usually break them in half and on this occasion I was using odd-shaped fragments which added up to less than a whole brick. They took about 8 minutes. (In the UK you can also get fuel as round tablets, which I find an inconvenient shape and they leave more of a residue, so I avoid them.)

I have both sizes of stove. The big one takes up more space, but the space isn't wasted as you can fit more stuff inside it. It should come fully packed with fuel, but I take some of the fuel out and replace it with a lighter and some tinder and a tea-spoon. The small one holds less stuff but will fit in places the big one won't. In particular, it will fit inside a Trangia mess tin with plenty of space left over, and together they form a nice little system for hiking.

I normally use the stoves for making coffee in the evening and morning, and sometimes noodles in the evening, when camping solo. Although this is outdoors there is usually no wind at those times, and they perform in the wild much as they do in the above test. I once tried to use one on a beach in the afternoon, and there was wind and I basically gave up (it started to rain and I was with other people who wanted to go home).