Mixed 10/100 and Gigabyte network

[ol' boy]

Currently my interent connection comes via UltraWAP in Station Infrastructure Mode (its tethered to my phone)
Sometimes i remove the UltraWAP and have a proper 3G Modem with a 4 port LAN in its place....

Either way, both those devices are 10/100

I enable DHCP in the UltraWAP or 3G Modem to control the LAN (PS3, WDTV, VU+, Dreambox, PC's and laptops)
There is also another Access Point on the LAN to broadcast to those portable devices.

So far, all works well..... and looks like the below

Phone > UltraWAP > 8 port switch > PS3/Vu+/WDTV/Dreambox/WiFi AP > portable devices

I am going to introduce a 10/100/1000 Wireless Router and a 10/100/1000 8 Port switch, replacing my old 10/100 switch and old Access Point.

My question is this... If i keep the DHCP enabled on the UltrapWAP (which is only 10/100) will all the data packets be slowed as they will have to travel up and down the only 10/100 leg on the network.

If i make the new 10/100/1000 4 port wireless router handle the DHCP but configure it with a fixed gateway address for the UltraWAP (internet)

Will that let the network work as fast as it can, while just leaving interent access (which is slow anyway) via the only 10/100 device, so it is doesn't have to suffer any data flow between other devices (like it does when it is handling the DHCP)

All my wired LAN devices have fixed address.
The new WiFi Router has 4 x 10/100/1000 ports and also a WAN port.

The outcome i'm hoping for is; a gigabyte wired network with wireless N for HD streaming to portable devices, with access to the net via a tethered phone or dedicated 3G modem.

[autotuner]

DHCP won't slow you down much. Once your devices have an address they will only talk to the DHCP server at refresh time (50% of lease time) or if they are forced to do a refresh via a boot etc.
Otherwise the devices will talk to each other via the switch, if both devices are 1Gb, then you will not be slowed (you'll never really get 1Gb).

They don't keep talking to the DHCP server.

[ol' boy]

Ok.... in my current config, it is the Phone that is being the DHCP...

When i use my laptop, i can either connect direct to my Phone or to my AP (which is on my wired LAN).

When using the laptop, it is more than twice as fast for internet work and downloading if i am connected direct to the phone (one hop).

If i wish to stream from the Vu+, i can either have the lappy connected to the AP or Phone, but it only really works properly if the laptop is connected to AP, thus taking the load off the Phone, which is rather obvious.

Hoping when the new Wireless N Router turns up, that i can leave the phone connected to the UltraWAP feeding the wired LAN... and enjoy both HD Streaming and good Internet and Downloading speeds, without having to jump direct to Phone.