Problems with clients

Hello everyone, it´s a pleasure to have the possibilitie to be here asking people who really knows this stuff, trusting we´ll get for certain your help.
Today I need your support for the following problem:
I bought a Mikrotik license, I got a flash IDE to install in my server, the version of the program is 2.9.46 I think, and I have 10 clients for the moment. I don´t want to continue installing service to new clients yet because a strange problem has been happening in my network.
I configured two interfaces, one for the Local and the other correspondig to the internet. I built the clients as simple queues, and then set the interface local as ARP-reply only, so that the mac-address of the bridge of a client had a determined IP address which belonged for that client (then obviously I added the ARP entries).
First all seemed to work properly, but in a few hours clients call telling the service was too slow, and many web pages couldn´t be opened.
I disabled all filter rules, but it seem to be the same.
For more details, I have 1 mb (not lineal) which the server distributes trough the network. I´m thinking of take out the mikrotik server until I can repair this problem, because some time ago, the same clients were conected to an ap which received signal only from a router (directly) and, altough I have no control over it, all worked faster.

Thanks a lot, and expect your help eagerly!

Hi ;
Really i don’t have a very clear idea about ARP , but why you not using the ARP as enabled ? .
i am using it on this way and there is no problem .
one time i changed it to reply-only when i read an article about blocking the ping and the browsing stopped then i return using ARP enabled .
with best regards .