Milestone outperforming Galaxy Nexus on mobile data connection speed

I recently switched from a Motorola Milestone to a Samsung Galaxy Nexus, and it seems the quality of my mobile data connections drops considerably between the devices without any apparent reason. The Motorola device can get up to 2mbps, while the Nexus struggles at ~150kbps. The *#*#4636#*#* menu on both devices shows no noticeable differences. The tests were made 20 minutes apart using the same SIM card. In summary: **Is there any configuration that can interfere so heavily on the way the data connection operates? If not, can it be a Radio/Baseband problem?** I'm using the 'stock' Google Rom (yakju) on the Galaxy Nexus, while the Milestone is using a custom Rom (ShadowMod 2.3), although it's behavior was the same on stock Froyo 2.2.